diff --git a/internal/registry/model_definitions.go b/internal/registry/model_definitions.go
index 0dd537b4f..72ac3324a 100644
--- a/internal/registry/model_definitions.go
+++ b/internal/registry/model_definitions.go
@@ -152,6 +152,20 @@ func GetGeminiCLIModels() []*ModelInfo {
 			OutputTokenLimit:           65536,
 			SupportedGenerationMethods: []string{"generateContent", "countTokens", "createCachedContent", "batchGenerateContent"},
 		},
+		{
+			ID:                         "gemini-2.5-flash-image-preview",
+			Object:                     "model",
+			Created:                    time.Now().Unix(),
+			OwnedBy:                    "google",
+			Type:                       "gemini",
+			Name:                       "models/gemini-2.5-flash-image-preview",
+			Version:                    "2.5",
+			DisplayName:                "Gemini 2.5 Flash Image Preview",
+			Description:                "State-of-the-art image generation and editing model.",
+			InputTokenLimit:            1048576,
+			OutputTokenLimit:           8192,
+			SupportedGenerationMethods: []string{"generateContent", "countTokens", "createCachedContent", "batchGenerateContent"},
+		},
 	}
 }
 
diff --git a/internal/runtime/executor/claude_executor.go b/internal/runtime/executor/claude_executor.go
index 10ec69233..5c942b12f 100644
--- a/internal/runtime/executor/claude_executor.go
+++ b/internal/runtime/executor/claude_executor.go
@@ -144,8 +144,8 @@ func (e *ClaudeExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 		defer close(out)
 		defer func() { _ = resp.Body.Close() }()
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/runtime/executor/codex_executor.go b/internal/runtime/executor/codex_executor.go
index 48209153e..38c0507db 100644
--- a/internal/runtime/executor/codex_executor.go
+++ b/internal/runtime/executor/codex_executor.go
@@ -189,8 +189,8 @@ func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 		defer close(out)
 		defer func() { _ = resp.Body.Close() }()
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/runtime/executor/gemini_cli_executor.go b/internal/runtime/executor/gemini_cli_executor.go
index 6643417a1..a96ca0631 100644
--- a/internal/runtime/executor/gemini_cli_executor.go
+++ b/internal/runtime/executor/gemini_cli_executor.go
@@ -212,8 +212,8 @@ func (e *GeminiCLIExecutor) ExecuteStream(ctx context.Context, auth *cliproxyaut
 			defer func() { _ = resp.Body.Close() }()
 			if opts.Alt == "" {
 				scanner := bufio.NewScanner(resp.Body)
-				buf := make([]byte, 1024*1024)
-				scanner.Buffer(buf, 1024*1024)
+				buf := make([]byte, 20_971_520)
+				scanner.Buffer(buf, 20_971_520)
 				var param any
 				for scanner.Scan() {
 					line := scanner.Bytes()
diff --git a/internal/runtime/executor/gemini_executor.go b/internal/runtime/executor/gemini_executor.go
index 38c55742d..2015e15d0 100644
--- a/internal/runtime/executor/gemini_executor.go
+++ b/internal/runtime/executor/gemini_executor.go
@@ -173,8 +173,8 @@ func (e *GeminiExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.A
 		defer close(out)
 		defer func() { _ = resp.Body.Close() }()
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/runtime/executor/iflow_executor.go b/internal/runtime/executor/iflow_executor.go
index 7768fd848..c8d233664 100644
--- a/internal/runtime/executor/iflow_executor.go
+++ b/internal/runtime/executor/iflow_executor.go
@@ -141,8 +141,8 @@ func (e *IFlowExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Au
 		defer func() { _ = resp.Body.Close() }()
 
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/runtime/executor/openai_compat_executor.go b/internal/runtime/executor/openai_compat_executor.go
index 356681cda..7d409f5d5 100644
--- a/internal/runtime/executor/openai_compat_executor.go
+++ b/internal/runtime/executor/openai_compat_executor.go
@@ -133,8 +133,8 @@ func (e *OpenAICompatExecutor) ExecuteStream(ctx context.Context, auth *cliproxy
 		defer close(out)
 		defer func() { _ = resp.Body.Close() }()
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/runtime/executor/qwen_executor.go b/internal/runtime/executor/qwen_executor.go
index 072a1b4f2..dcc02474a 100644
--- a/internal/runtime/executor/qwen_executor.go
+++ b/internal/runtime/executor/qwen_executor.go
@@ -126,8 +126,8 @@ func (e *QwenExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Aut
 		defer close(out)
 		defer func() { _ = resp.Body.Close() }()
 		scanner := bufio.NewScanner(resp.Body)
-		buf := make([]byte, 1024*1024)
-		scanner.Buffer(buf, 1024*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		var param any
 		for scanner.Scan() {
 			line := scanner.Bytes()
diff --git a/internal/translator/claude/gemini/claude_gemini_response.go b/internal/translator/claude/gemini/claude_gemini_response.go
index 23950fdb4..0c90398ec 100644
--- a/internal/translator/claude/gemini/claude_gemini_response.go
+++ b/internal/translator/claude/gemini/claude_gemini_response.go
@@ -331,8 +331,8 @@ func ConvertClaudeResponseToGeminiNonStream(_ context.Context, modelName string,
 	streamingEvents := make([][]byte, 0)
 
 	scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-	buffer := make([]byte, 10240*1024)
-	scanner.Buffer(buffer, 10240*1024)
+	buffer := make([]byte, 20_971_520)
+	scanner.Buffer(buffer, 20_971_520)
 	for scanner.Scan() {
 		line := scanner.Bytes()
 		// log.Debug(string(line))
diff --git a/internal/translator/claude/openai/responses/claude_openai-responses_response.go b/internal/translator/claude/openai/responses/claude_openai-responses_response.go
index ab88ab324..77507f97b 100644
--- a/internal/translator/claude/openai/responses/claude_openai-responses_response.go
+++ b/internal/translator/claude/openai/responses/claude_openai-responses_response.go
@@ -445,8 +445,8 @@ func ConvertClaudeResponseToOpenAIResponsesNonStream(_ context.Context, _ string
 		// Use a simple scanner to iterate through raw bytes
 		// Note: extremely large responses may require increasing the buffer
 		scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-		buf := make([]byte, 10240*1024)
-		scanner.Buffer(buf, 10240*1024)
+		buf := make([]byte, 20_971_520)
+		scanner.Buffer(buf, 20_971_520)
 		for scanner.Scan() {
 			line := scanner.Bytes()
 			if !bytes.HasPrefix(line, dataTag) {
diff --git a/internal/translator/codex/claude/codex_claude_response.go b/internal/translator/codex/claude/codex_claude_response.go
index e78eae05b..5023f381b 100644
--- a/internal/translator/codex/claude/codex_claude_response.go
+++ b/internal/translator/codex/claude/codex_claude_response.go
@@ -181,8 +181,8 @@ func ConvertCodexResponseToClaude(_ context.Context, _ string, originalRequestRa
 //   - string: A Claude Code-compatible JSON response containing all message content and metadata
 func ConvertCodexResponseToClaudeNonStream(_ context.Context, _ string, originalRequestRawJSON, _ []byte, rawJSON []byte, _ *any) string {
 	scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-	buffer := make([]byte, 10240*1024)
-	scanner.Buffer(buffer, 10240*1024)
+	buffer := make([]byte, 20_971_520)
+	scanner.Buffer(buffer, 20_971_520)
 	revNames := buildReverseMapFromClaudeOriginalShortToOriginal(originalRequestRawJSON)
 
 	for scanner.Scan() {
diff --git a/internal/translator/codex/gemini/codex_gemini_response.go b/internal/translator/codex/gemini/codex_gemini_response.go
index 20d255a4b..b0bd8cba7 100644
--- a/internal/translator/codex/gemini/codex_gemini_response.go
+++ b/internal/translator/codex/gemini/codex_gemini_response.go
@@ -153,8 +153,8 @@ func ConvertCodexResponseToGemini(_ context.Context, modelName string, originalR
 //   - string: A Gemini-compatible JSON response containing all message content and metadata
 func ConvertCodexResponseToGeminiNonStream(_ context.Context, modelName string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) string {
 	scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-	buffer := make([]byte, 10240*1024)
-	scanner.Buffer(buffer, 10240*1024)
+	buffer := make([]byte, 20_971_520)
+	scanner.Buffer(buffer, 20_971_520)
 	for scanner.Scan() {
 		line := scanner.Bytes()
 		// log.Debug(string(line))
diff --git a/internal/translator/codex/openai/responses/codex_openai-responses_response.go b/internal/translator/codex/openai/responses/codex_openai-responses_response.go
index f29c26631..8f8d53479 100644
--- a/internal/translator/codex/openai/responses/codex_openai-responses_response.go
+++ b/internal/translator/codex/openai/responses/codex_openai-responses_response.go
@@ -30,8 +30,8 @@ func ConvertCodexResponseToOpenAIResponses(ctx context.Context, modelName string
 // from a non-streaming OpenAI Chat Completions response.
 func ConvertCodexResponseToOpenAIResponsesNonStream(_ context.Context, modelName string, originalRequestRawJSON, requestRawJSON, rawJSON []byte, _ *any) string {
 	scanner := bufio.NewScanner(bytes.NewReader(rawJSON))
-	buffer := make([]byte, 10240*1024)
-	scanner.Buffer(buffer, 10240*1024)
+	buffer := make([]byte, 20_971_520)
+	scanner.Buffer(buffer, 20_971_520)
 	dataTag := []byte("data:")
 	for scanner.Scan() {
 		line := scanner.Bytes()