diff --git a/handler/ai.go b/handler/ai.go
index 26d5d7d..0b60f9d 100644
--- a/handler/ai.go
+++ b/handler/ai.go
@@ -9,8 +9,10 @@ import (
 	"mime"
 	"mime/multipart"
 	"net/http"
+	"net/textproto"
 	"strings"
 
+	"github.com/basketikun/infinite-canvas/model"
 	"github.com/basketikun/infinite-canvas/service"
 )
 
@@ -84,6 +86,12 @@ func proxyAIRequest(w http.ResponseWriter, r *http.Request, path string) {
 		Fail(w, "AI 接口请求失败")
 		return
 	}
+	body, contentType, err = adaptAIRequestForChannel(body, contentType, path, channel)
+	if err != nil {
+		log.Printf("AI proxy adapt request failed: model=%s path=%s err=%v", modelName, path, err)
+		Fail(w, "AI 接口请求失败")
+		return
+	}
 	path = resolveAIProxyPath(channel.BaseURL, modelName, path)
 	request, err := http.NewRequest(http.MethodPost, service.BuildModelChannelURL(channel, path), bytes.NewReader(body))
 	if err != nil {
@@ -140,6 +148,90 @@ func copyAIResponse(w http.ResponseWriter, request *http.Request, onFailure func
 	_, _ = io.Copy(w, response.Body)
 }
 
+func adaptAIRequestForChannel(body []byte, contentType string, path string, channel model.ModelChannel) ([]byte, string, error) {
+	if path != "/images/generations" && path != "/images/edits" {
+		return body, contentType, nil
+	}
+	format := strings.ToLower(strings.TrimSpace(channel.RequestOptions.ImageResponseFormat))
+	if format == "" {
+		if strings.EqualFold(strings.TrimSpace(channel.Compatibility), "sub2api") {
+			format = "url"
+		} else {
+			format = "b64_json"
+		}
+	}
+	if format != "url" && format != "b64_json" {
+		return body, contentType, nil
+	}
+	if strings.HasPrefix(contentType, "multipart/form-data") {
+		return setMultipartField(body, contentType, "response_format", format)
+	}
+	var payload map[string]any
+	if err := json.Unmarshal(body, &payload); err != nil {
+		return nil, "", err
+	}
+	payload["response_format"] = format
+	nextBody, err := json.Marshal(payload)
+	if err != nil {
+		return nil, "", err
+	}
+	return nextBody, contentType, nil
+}
+
+func setMultipartField(body []byte, contentType string, fieldName string, value string) ([]byte, string, error) {
+	_, params, err := mime.ParseMediaType(contentType)
+	if err != nil {
+		return nil, "", err
+	}
+	reader := multipart.NewReader(bytes.NewReader(body), params["boundary"])
+	var buffer bytes.Buffer
+	writer := multipart.NewWriter(&buffer)
+	written := false
+	for {
+		part, err := reader.NextPart()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return nil, "", err
+		}
+		if part.FormName() == fieldName && part.FileName() == "" {
+			if err := writer.WriteField(fieldName, value); err != nil {
+				_ = part.Close()
+				return nil, "", err
+			}
+			written = true
+			_ = part.Close()
+			continue
+		}
+		header := make(textproto.MIMEHeader, len(part.Header))
+		for key, values := range part.Header {
+			copied := make([]string, len(values))
+			copy(copied, values)
+			header[key] = copied
+		}
+		target, err := writer.CreatePart(header)
+		if err != nil {
+			_ = part.Close()
+			return nil, "", err
+		}
+		if _, err := io.Copy(target, part); err != nil {
+			_ = part.Close()
+			return nil, "", err
+		}
+		_ = part.Close()
+	}
+	if !written {
+		if err := writer.WriteField(fieldName, value); err != nil {
+			return nil, "", err
+		}
+	}
+	if err := writer.Close(); err != nil {
+		return nil, "", err
+	}
+	return buffer.Bytes(), writer.FormDataContentType(), nil
+}
+
 func readAIRequest(r *http.Request) ([]byte, string, string, error) {
 	contentType := r.Header.Get("Content-Type")
 	body, err := io.ReadAll(r.Body)
diff --git a/handler/ai_test.go b/handler/ai_test.go
index 2eaa897..6c0c8a4 100644
--- a/handler/ai_test.go
+++ b/handler/ai_test.go
@@ -1,8 +1,13 @@
 package handler
 
 import (
+	"bytes"
+	"encoding/json"
+	"mime/multipart"
 	"strings"
 	"testing"
+
+	"github.com/basketikun/infinite-canvas/model"
 )
 
 func TestAIUpstreamErrorDetail(t *testing.T) {
@@ -25,3 +30,51 @@ func TestSafeUpstreamTextTruncates(t *testing.T) {
 		t.Fatalf("truncated rune length = %d", len([]rune(got)))
 	}
 }
+
+func TestAdaptAIRequestForSub2APIImagesUsesURLResponseFormat(t *testing.T) {
+	body, contentType, err := adaptAIRequestForChannel([]byte(`{"model":"gpt-image-1","prompt":"cat"}`), "application/json", "/images/generations", model.ModelChannel{Compatibility: "sub2api"})
+	if err != nil {
+		t.Fatalf("adaptAIRequestForChannel returned error: %v", err)
+	}
+	if contentType != "application/json" {
+		t.Fatalf("contentType = %q", contentType)
+	}
+	var payload map[string]any
+	if err := json.Unmarshal(body, &payload); err != nil {
+		t.Fatalf("invalid json body: %v", err)
+	}
+	if got := payload["response_format"]; got != "url" {
+		t.Fatalf("response_format = %#v, want url", got)
+	}
+}
+
+func TestAdaptAIRequestForSub2APIImageEditsUpdatesMultipartResponseFormat(t *testing.T) {
+	var input bytes.Buffer
+	writer := multipart.NewWriter(&input)
+	_ = writer.WriteField("model", "gpt-image-1")
+	_ = writer.WriteField("response_format", "b64_json")
+	part, err := writer.CreateFormFile("image", "input.png")
+	if err != nil {
+		t.Fatalf("CreateFormFile: %v", err)
+	}
+	_, _ = part.Write([]byte("png"))
+	if err := writer.Close(); err != nil {
+		t.Fatalf("Close multipart writer: %v", err)
+	}
+
+	body, contentType, err := adaptAIRequestForChannel(input.Bytes(), writer.FormDataContentType(), "/images/edits", model.ModelChannel{Compatibility: "sub2api"})
+	if err != nil {
+		t.Fatalf("adaptAIRequestForChannel returned error: %v", err)
+	}
+	reader := multipart.NewReader(bytes.NewReader(body), strings.TrimPrefix(contentType, "multipart/form-data; boundary="))
+	form, err := reader.ReadForm(1024)
+	if err != nil {
+		t.Fatalf("ReadForm: %v", err)
+	}
+	if got := form.Value["response_format"]; len(got) != 1 || got[0] != "url" {
+		t.Fatalf("response_format = %#v, want [url]", got)
+	}
+	if files := form.File["image"]; len(files) != 1 || files[0].Filename != "input.png" {
+		t.Fatalf("image file = %#v", files)
+	}
+}
diff --git a/model/setting.go b/model/setting.go
index d6d4a1f..8b4eb3f 100644
--- a/model/setting.go
+++ b/model/setting.go
@@ -11,14 +11,23 @@ const (
 
 // ModelChannel 模型渠道配置。
 type ModelChannel struct {
-	Protocol string   `json:"protocol"`
-	Name     string   `json:"name"`
-	BaseURL  string   `json:"baseUrl"`
-	APIKey   string   `json:"apiKey"`
-	Models   []string `json:"models"`
-	Weight   int      `json:"weight"`
-	Enabled  bool     `json:"enabled"`
-	Remark   string   `json:"remark"`
+	Protocol       string              `json:"protocol"`
+	Compatibility  string              `json:"compatibility"`
+	Name           string              `json:"name"`
+	BaseURL        string              `json:"baseUrl"`
+	APIKey         string              `json:"apiKey"`
+	Models         []string            `json:"models"`
+	Weight         int                 `json:"weight"`
+	Enabled        bool                `json:"enabled"`
+	Remark         string              `json:"remark"`
+	RequestOptions ModelRequestOptions `json:"requestOptions"`
+}
+
+// ModelRequestOptions 控制 OpenAI 兼容接口的可选请求参数。
+type ModelRequestOptions struct {
+	// ImageResponseFormat 为图片生成/编辑请求设置 response_format。
+	// OpenAI 默认使用 b64_json；Sub2API 推荐使用 url，避免部分上游不返回 b64_json。
+	ImageResponseFormat string `json:"imageResponseFormat"`
 }
 
 // ModelCost 模型算力点配置。
diff --git a/service/settings.go b/service/settings.go
index 121c802..f048ac0 100644
--- a/service/settings.go
+++ b/service/settings.go
@@ -129,6 +129,8 @@ func normalizePrivateSetting(setting model.PrivateSetting) model.PrivateSetting
 		if setting.Channels[i].Protocol == "" {
 			setting.Channels[i].Protocol = "openai"
 		}
+		setting.Channels[i].Compatibility = normalizeChannelCompatibility(setting.Channels[i].Compatibility)
+		setting.Channels[i].RequestOptions = normalizeModelRequestOptions(setting.Channels[i].Compatibility, setting.Channels[i].RequestOptions)
 		if setting.Channels[i].Models == nil {
 			setting.Channels[i].Models = []string{}
 		}
@@ -202,12 +204,54 @@ func SelectModelChannel(modelName string) (model.ModelChannel, error) {
 func BuildModelChannelURL(channel model.ModelChannel, path string) string {
 	baseURL := normalizeModelChannelBaseURL(channel.BaseURL)
 	lowerBaseURL := strings.ToLower(baseURL)
-	if !strings.HasSuffix(lowerBaseURL, "/v1") && !strings.HasSuffix(lowerBaseURL, "/api/v3") && !strings.HasSuffix(lowerBaseURL, "/api/plan/v3") {
+	if !hasModelChannelVersionSuffix(lowerBaseURL) && !strings.HasSuffix(lowerBaseURL, "/api/v3") && !strings.HasSuffix(lowerBaseURL, "/api/plan/v3") {
 		baseURL += "/v1"
 	}
 	return baseURL + path
 }
 
+func hasModelChannelVersionSuffix(baseURL string) bool {
+	pathValue := baseURL
+	if parsed, err := url.Parse(baseURL); err == nil && parsed.Scheme != "" && parsed.Host != "" {
+		pathValue = parsed.Path
+	}
+	pathValue = strings.TrimRight(pathValue, "/")
+	if pathValue == "" {
+		return false
+	}
+	segment := pathValue
+	if slash := strings.LastIndex(pathValue, "/"); slash >= 0 {
+		segment = pathValue[slash+1:]
+	}
+	segment = strings.ToLower(strings.TrimSpace(segment))
+	if len(segment) < 2 || segment[0] != 'v' || !isASCIIDigit(segment[1]) {
+		return false
+	}
+	i := 1
+	for i < len(segment) && isASCIIDigit(segment[i]) {
+		i++
+	}
+	if i == len(segment) {
+		return true
+	}
+	if segment[i] == '.' {
+		i++
+		if i == len(segment) || !isASCIIDigit(segment[i]) {
+			return false
+		}
+		for i < len(segment) && isASCIIDigit(segment[i]) {
+			i++
+		}
+		return i == len(segment)
+	}
+	suffix := segment[i:]
+	return strings.HasPrefix(suffix, "alpha") || strings.HasPrefix(suffix, "beta") || strings.HasPrefix(suffix, "preview")
+}
+
+func isASCIIDigit(ch byte) bool {
+	return ch >= '0' && ch <= '9'
+}
+
 func normalizeModelChannelBaseURL(baseURL string) string {
 	baseURL = strings.TrimRight(strings.TrimSpace(baseURL), "/")
 	parsed, err := url.Parse(baseURL)
@@ -299,6 +343,8 @@ func normalizeModelChannel(channel model.ModelChannel) model.ModelChannel {
 	if channel.Protocol == "" {
 		channel.Protocol = "openai"
 	}
+	channel.Compatibility = normalizeChannelCompatibility(channel.Compatibility)
+	channel.RequestOptions = normalizeModelRequestOptions(channel.Compatibility, channel.RequestOptions)
 	if channel.Models == nil {
 		channel.Models = []string{}
 	}
@@ -308,6 +354,30 @@ func normalizeModelChannel(channel model.ModelChannel) model.ModelChannel {
 	return channel
 }
 
+func normalizeChannelCompatibility(value string) string {
+	switch strings.ToLower(strings.TrimSpace(value)) {
+	case "sub2api":
+		return "sub2api"
+	default:
+		return "openai"
+	}
+}
+
+func normalizeModelRequestOptions(compatibility string, options model.ModelRequestOptions) model.ModelRequestOptions {
+	format := strings.ToLower(strings.TrimSpace(options.ImageResponseFormat))
+	switch format {
+	case "url", "b64_json":
+		options.ImageResponseFormat = format
+	default:
+		if normalizeChannelCompatibility(compatibility) == "sub2api" {
+			options.ImageResponseFormat = "url"
+		} else {
+			options.ImageResponseFormat = "b64_json"
+		}
+	}
+	return options
+}
+
 func resolveAdminChannel(index *int, channel model.ModelChannel) (model.ModelChannel, error) {
 	resolved := normalizeModelChannel(channel)
 	if strings.TrimSpace(resolved.APIKey) == "" {
@@ -380,6 +450,9 @@ func testAdminChannelModel(channel model.ModelChannel, modelName string) (string
 	if strings.TrimSpace(modelName) == "" {
 		return "", errors.New("缺少模型名称")
 	}
+	if isImageModelName(modelName) {
+		return testAdminImageChannelModel(channel, modelName)
+	}
 	body, _ := json.Marshal(map[string]any{
 		"model": modelName,
 		"messages": []map[string]string{{
@@ -416,6 +489,40 @@ func testAdminChannelModel(channel model.ModelChannel, modelName string) (string
 	return "ok", nil
 }
 
+func testAdminImageChannelModel(channel model.ModelChannel, modelName string) (string, error) {
+	format := strings.ToLower(strings.TrimSpace(channel.RequestOptions.ImageResponseFormat))
+	if format == "" {
+		if strings.EqualFold(strings.TrimSpace(channel.Compatibility), "sub2api") {
+			format = "url"
+		} else {
+			format = "b64_json"
+		}
+	}
+	body, _ := json.Marshal(map[string]any{
+		"model":           modelName,
+		"prompt":          "test",
+		"n":               1,
+		"size":            "1024x1024",
+		"response_format": format,
+	})
+	request, err := http.NewRequest(http.MethodPost, BuildModelChannelURL(channel, "/images/generations"), strings.NewReader(string(body)))
+	if err != nil {
+		return "", err
+	}
+	request.Header.Set("Authorization", "Bearer "+channel.APIKey)
+	request.Header.Set("Content-Type", "application/json")
+	response, err := adminModelHTTPClient.Do(request)
+	if err != nil {
+		return "", safeMessageError{message: "测试失败：上游接口无响应或网络不可达"}
+	}
+	defer response.Body.Close()
+	responseBody, _ := io.ReadAll(response.Body)
+	if response.StatusCode >= http.StatusBadRequest {
+		return "", readAdminChannelError(responseBody, response.StatusCode, "测试失败")
+	}
+	return "ok", nil
+}
+
 func testArkSeedanceChannelModel(channel model.ModelChannel, modelName string) (string, error) {
 	if strings.TrimSpace(modelName) == "" {
 		return "", errors.New("缺少模型名称")
diff --git a/service/settings_test.go b/service/settings_test.go
index 27c6b2e..eb29c68 100644
--- a/service/settings_test.go
+++ b/service/settings_test.go
@@ -1,6 +1,7 @@
 package service
 
 import (
+	"encoding/json"
 	"net/http"
 	"net/http/httptest"
 	"reflect"
@@ -61,6 +62,56 @@ func TestBuildModelChannelURLNormalizesArkPlanTaskPath(t *testing.T) {
 	}
 }
 
+func TestBuildModelChannelURLAcceptsVersionedSub2APIBaseURL(t *testing.T) {
+	got := BuildModelChannelURL(model.ModelChannel{BaseURL: "https://sub2api.example.com/v1"}, "/images/generations")
+	want := "https://sub2api.example.com/v1/images/generations"
+	if got != want {
+		t.Fatalf("BuildModelChannelURL = %q, want %q", got, want)
+	}
+}
+
+func TestNormalizePrivateSettingDefaultsSub2APIImageResponseFormatToURL(t *testing.T) {
+	setting := normalizePrivateSetting(model.PrivateSetting{Channels: []model.ModelChannel{{Compatibility: "sub2api"}}})
+	if got := setting.Channels[0].RequestOptions.ImageResponseFormat; got != "url" {
+		t.Fatalf("image response format = %q, want url", got)
+	}
+}
+
+func TestAdminTestChannelModelUsesImageGenerationProbeForImageModels(t *testing.T) {
+	var gotPath string
+	var gotPayload map[string]any
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotPath = r.URL.Path
+		if err := json.NewDecoder(r.Body).Decode(&gotPayload); err != nil {
+			t.Fatalf("Decode request body: %v", err)
+		}
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(`{"data":[{"url":"https://example.com/image.png"}]}`))
+	}))
+	defer server.Close()
+
+	result, err := testAdminChannelModel(model.ModelChannel{
+		Compatibility: "sub2api",
+		BaseURL:       server.URL + "/v1",
+		APIKey:        "test-key",
+	}, "gpt-image-2")
+	if err != nil {
+		t.Fatalf("testAdminChannelModel returned error: %v", err)
+	}
+	if result != "ok" {
+		t.Fatalf("result = %q, want ok", result)
+	}
+	if gotPath != "/v1/images/generations" {
+		t.Fatalf("path = %q, want /v1/images/generations", gotPath)
+	}
+	if gotPayload["model"] != "gpt-image-2" {
+		t.Fatalf("model = %#v", gotPayload["model"])
+	}
+	if gotPayload["response_format"] != "url" {
+		t.Fatalf("response_format = %#v, want url", gotPayload["response_format"])
+	}
+}
+
 func TestNormalizeSettingsPublishesEnabledChannelModelsAndRepairsDefaults(t *testing.T) {
 	settings := normalizeSettings(model.Settings{
 		Public: model.PublicSetting{
diff --git a/web/src/services/api/admin.ts b/web/src/services/api/admin.ts
index d4971ab..37647d0 100644
--- a/web/src/services/api/admin.ts
+++ b/web/src/services/api/admin.ts
@@ -158,6 +158,7 @@ export async function deleteAdminAsset(token: string, id: string) {
 
 export type AdminModelChannel = {
     protocol: "openai";
+    compatibility: "openai" | "sub2api";
     name: string;
     baseUrl: string;
     apiKey: string;
@@ -165,6 +166,9 @@ export type AdminModelChannel = {
     weight: number;
     enabled: boolean;
     remark: string;
+    requestOptions: {
+        imageResponseFormat: "b64_json" | "url";
+    };
 };
 
 export type AdminPublicModelChannelSettings = {