diff --git a/backend/internal/service/provider.go b/backend/internal/service/provider.go
index 39de9f75e..a611e10fe 100644
--- a/backend/internal/service/provider.go
+++ b/backend/internal/service/provider.go
@@ -327,9 +327,6 @@ func systemChannelIDFromBaseURL(baseURL string) string {
 }
 
 func runImageTask(ctx context.Context, input canvasGenerationInput) (map[string]interface{}, error) {
-	if input.Config.TransparentBackground == "true" && !supportsTransparentImageBackground(input.Config) {
-		return nil, errors.New("当前模型不支持透明背景，请关闭透明背景或切换至 GPT Image 1 系列模型")
-	}
 	var payload imageResponse
 	if len(input.ReferenceImages) > 0 || input.Mask != nil {
 		body := &bytes.Buffer{}
@@ -1781,12 +1778,6 @@ func isArkPlanVideoConfig(config providerConfig) bool {
 	return strings.Contains(strings.ToLower(config.BaseURL), "/api/plan/v3")
 }
 
-// 透明背景必须按模型能力显式开放，避免上游静默忽略参数后返回不透明图片。
-func supportsTransparentImageBackground(config providerConfig) bool {
-	model := strings.ToLower(strings.TrimSpace(config.Model))
-	return strings.EqualFold(strings.TrimSpace(config.APIFormat), "openai") && (model == "gpt-image-1" || strings.HasPrefix(model, "gpt-image-1-") || strings.HasPrefix(model, "gpt-image-1."))
-}
-
 func normalizeImageQuality(value string) string {
 	switch strings.ToLower(strings.TrimSpace(value)) {
 	case "1k":
diff --git a/web/src/components/image-settings-panel.tsx b/web/src/components/image-settings-panel.tsx
index 12f17d14e..d87ebde2a 100644
--- a/web/src/components/image-settings-panel.tsx
+++ b/web/src/components/image-settings-panel.tsx
@@ -2,7 +2,7 @@ import { type ReactNode, useState } from "react";
 import { ConfigProvider, Switch } from "antd";
 
 import { type CanvasTheme } from "@/lib/canvas-theme";
-import { supportsTransparentImageBackground, type AiConfig } from "@/stores/use-config-store";
+import { type AiConfig } from "@/stores/use-config-store";
 
 const qualityOptions = [
     { value: "auto", label: "自动" },
@@ -19,6 +19,7 @@ const aspectOptions = [
     { value: "4:3", label: "4:3", width: 1360, height: 1024, icon: "landscape" },
     { value: "3:4", label: "3:4", width: 1024, height: 1360, icon: "portrait" },
     { value: "16:9", label: "16:9", width: 1824, height: 1024, icon: "landscape" },
+    { value: "21:9", label: "21:9", size: "2352x1008", width: 2352, height: 1008, icon: "landscape" },
     { value: "9:16", label: "9:16", width: 1024, height: 1824, icon: "portrait" },
     { value: "1:1-2k", label: "1:1(2k)", size: "2048x2048", width: 2048, height: 2048, icon: "square" },
     { value: "16:9-2k", label: "16:9(2k)", size: "2048x1152", width: 2048, height: 1152, icon: "landscape" },
@@ -43,7 +44,6 @@ export function ImageSettingsPanel({ config, onConfigChange, theme, showTitle =
     const [snapDimensionToStep, setSnapDimensionToStep] = useState(true);
     const quality = config.quality || "auto";
     const transparentBackground = config.transparentBackground === "true";
-    const transparentBackgroundSupported = supportsTransparentImageBackground(config, config.model || config.imageModel);
     const count = Math.max(1, Math.min(maxCount, Math.floor(Math.abs(Number(config.count)) || 1)));
     const activeSize = config.size || "auto";
     const selectedAspect = aspectOptions.find((item) => (item.size || item.value) === activeSize || item.value === activeSize);
@@ -84,15 +84,14 @@ export function ImageSettingsPanel({ config, onConfigChange, theme, showTitle =
                 <div className="flex items-center justify-between gap-3">
                     <div className="min-w-0">
                         <SettingTitle color={theme.node.muted}>透明背景</SettingTitle>
-                        <div className="mt-1 text-[11px]" style={{ color: transparentBackgroundSupported ? theme.node.muted : theme.accent.danger }}>
-                            {transparentBackgroundSupported ? "输出保留 Alpha 通道的 PNG" : transparentBackground ? "当前模型不支持，生成会被阻止" : "当前模型不支持透明背景"}
+                        <div className="mt-1 text-[11px]" style={{ color: theme.node.muted }}>
+                            请求模型输出保留 Alpha 通道的 PNG
                         </div>
                     </div>
-                    <span title={transparentBackgroundSupported ? "使用透明背景生成 PNG 图片" : "仅 GPT Image 1 系列模型支持透明背景"} onMouseDown={(event) => event.stopPropagation()}>
+                    <span title="是否支持透明背景由当前模型接口决定" onMouseDown={(event) => event.stopPropagation()}>
                         <Switch
                             size="small"
                             checked={transparentBackground}
-                            disabled={!transparentBackgroundSupported && !transparentBackground}
                             onChange={(checked) => onConfigChange("transparentBackground", checked ? "true" : "false")}
                         />
                     </span>
diff --git a/web/src/services/api/image.ts b/web/src/services/api/image.ts
index 1e408edfc..c9a9a0d61 100644
--- a/web/src/services/api/image.ts
+++ b/web/src/services/api/image.ts
@@ -1,6 +1,6 @@
 import axios from "axios";
 
-import { buildApiUrl, isSystemProxyBaseUrl, resolveBackendApiUrl, resolveModelRequestConfig, supportsTransparentImageBackground, type AiConfig, type ModelChannel } from "@/stores/use-config-store";
+import { buildApiUrl, isSystemProxyBaseUrl, resolveBackendApiUrl, resolveModelRequestConfig, type AiConfig, type ModelChannel } from "@/stores/use-config-store";
 import { nanoid } from "nanoid";
 import { dataUrlToFile } from "@/lib/image-utils";
 import { buildImageReferencePromptText } from "@/lib/image-reference-prompt";
@@ -233,13 +233,6 @@ function readStatusError(status: number | undefined, fallback: string) {
     return status ? `${fallback}：${status}` : fallback;
 }
 
-function assertTransparentBackgroundSupported(config: AiConfig, model: string) {
-    if (config.transparentBackground !== "true") return;
-    if (!supportsTransparentImageBackground(config, model)) {
-        throw new Error("当前模型不支持透明背景，请关闭“透明背景”或切换至 GPT Image 1 系列模型");
-    }
-}
-
 function withSystemPrompt(config: AiConfig, prompt: string) {
     const systemPrompt = config.systemPrompt.trim();
     return systemPrompt ? `${systemPrompt}\n\n${prompt}` : prompt;
@@ -764,7 +757,6 @@ function parseGeminiImagePayload(payload: GeminiPayload) {
 
 export async function requestGeneration(config: AiConfig, prompt: string, options?: RequestOptions) {
     const selectedModel = config.model || config.imageModel;
-    assertTransparentBackgroundSupported(config, selectedModel);
     const requestConfig = resolveModelRequestConfig(config, selectedModel);
     const n = Math.max(1, Math.min(15, Math.floor(Math.abs(Number(config.count)) || 1)));
     if (requestConfig.apiFormat === "gemini") {
@@ -803,7 +795,6 @@ export async function requestGeneration(config: AiConfig, prompt: string, option
 
 export async function requestEdit(config: AiConfig, prompt: string, references: ReferenceImage[], mask?: ReferenceImage, options?: RequestOptions) {
     const selectedModel = config.model || config.imageModel;
-    assertTransparentBackgroundSupported(config, selectedModel);
     const requestConfig = resolveModelRequestConfig(config, selectedModel);
     const n = Math.max(1, Math.min(15, Math.floor(Math.abs(Number(config.count)) || 1)));
     const requestPrompt = buildImageReferencePromptText(prompt, references);
diff --git a/web/src/stores/use-config-store.ts b/web/src/stores/use-config-store.ts
index 5c51d4c4b..4fd17cced 100644
--- a/web/src/stores/use-config-store.ts
+++ b/web/src/stores/use-config-store.ts
@@ -383,13 +383,6 @@ export function resolveModelChannel(config: AiConfig, value: string) {
     return matched || config.channels[0] || createModelChannel({ id: "default", name: "默认渠道", baseUrl: config.baseUrl, apiKey: config.apiKey, apiFormat: config.apiFormat, models: config.models.map(modelOptionName) });
 }
 
-// 透明背景必须按模型能力显式开放，避免代理接口静默忽略参数后返回不透明图片。
-export function supportsTransparentImageBackground(config: AiConfig, value: string) {
-    const channel = resolveModelChannel(config, value);
-    const model = modelOptionName(value).trim().toLowerCase();
-    return channel.apiFormat === "openai" && (model === "gpt-image-1" || model.startsWith("gpt-image-1-") || model.startsWith("gpt-image-1."));
-}
-
 export function resolveModelRequestConfig(config: AiConfig, value: string) {
     const channel = resolveModelChannel(config, value);
     return {