diff --git a/backend/internal/service/image_output_accounting.go b/backend/internal/service/image_output_accounting.go
index 2f2bd6ae84..4ae6c5d7ca 100644
--- a/backend/internal/service/image_output_accounting.go
+++ b/backend/internal/service/image_output_accounting.go
@@ -99,16 +99,25 @@ func (c *openAIImageOutputCounter) addDataArray(data gjson.Result) {
 		return
 	}
 	items := data.Array()
-	count := len(items)
-	if count > c.maxDataCount {
-		c.maxDataCount = count
-	}
+	imageCount := 0
 	sizes := make([]string, 0, len(items))
 	for _, item := range items {
+		if !item.IsObject() {
+			continue
+		}
+		hasImageOutput := strings.TrimSpace(item.Get("url").String()) != "" ||
+			strings.TrimSpace(item.Get("b64_json").String()) != ""
+		if !hasImageOutput {
+			continue
+		}
+		imageCount++
 		if size := strings.TrimSpace(item.Get("size").String()); size != "" {
 			sizes = append(sizes, size)
 		}
 	}
+	if imageCount > c.maxDataCount {
+		c.maxDataCount = imageCount
+	}
 	if len(sizes) > 0 {
 		c.dataSizes = sizes
 	}
@@ -142,7 +151,7 @@ func (c *openAIImageOutputCounter) addImageOutputItem(item gjson.Result) {
 	if result == "" {
 		result = strings.TrimSpace(item.Get("url").String())
 	}
-	if result == "" && itemType != "image_generation.completed" {
+	if result == "" {
 		return
 	}
 	key := strings.TrimSpace(item.Get("id").String())
diff --git a/backend/internal/service/image_output_accounting_test.go b/backend/internal/service/image_output_accounting_test.go
new file mode 100644
index 0000000000..227f131e56
--- /dev/null
+++ b/backend/internal/service/image_output_accounting_test.go
@@ -0,0 +1,254 @@
+package service
+
+import (
+	"testing"
+)
+
+func TestOpenAIImageOutputCounter_TextOnlyMessage(t *testing.T) {
+	// Simulate a text-only response from /v1/responses
+	// The response.output_item.done event for a text message
+	sseBody := `data: {"type":"response.created","response":{"id":"resp_123"}}
+
+data: {"type":"response.in_progress","response":{"id":"resp_123"}}
+
+data: {"type":"response.output_item.added","item":{"id":"item_1","type":"message","role":"assistant","status":"in_progress"}}
+
+data: {"type":"response.output_text.delta","item_id":"item_1","output_index":0,"content_index":0,"delta":"Hello"}
+
+data: {"type":"response.output_text.done","item_id":"item_1","output_index":0,"content_index":0,"text":"Hello"}
+
+data: {"type":"response.output_item.done","item":{"id":"item_1","type":"message","role":"assistant","status":"completed","content":[{"type":"output_text","text":"Hello"}]}}
+
+data: {"type":"response.completed","response":{"id":"resp_123","output":[{"id":"item_1","type":"message","role":"assistant","status":"completed","content":[{"type":"output_text","text":"Hello"}]}],"usage":{"input_tokens":10,"output_tokens":5}}}
+
+data: [DONE]`
+
+	count := countOpenAIImageOutputsFromSSEBody(sseBody)
+	if count != 0 {
+		t.Errorf("expected 0 images for text-only message, got %d", count)
+	}
+}
+
+func TestOpenAIImageOutputCounter_NestedSub2API_StandardResponse(t *testing.T) {
+	// Simulate what a nested sub2api setup receives
+	// When the upstream sub2api returns a standard response, the downstream
+	// sub2api receives SSE events. This test verifies that no false positives
+	// occur.
+	sseBody := `data: {"type":"response.created","response":{"id":"resp_nested_1","object":"response","status":"in_progress"}}
+
+data: {"type":"response.in_progress","response":{"id":"resp_nested_1","object":"response","status":"in_progress"}}
+
+data: {"type":"response.output_item.added","item":{"id":"item_nested_1","type":"message","role":"assistant","status":"in_progress"}}
+
+data: {"type":"response.output_text.delta","item_id":"item_nested_1","output_index":0,"content_index":0,"delta":"你好"}
+
+data: {"type":"response.output_text.done","item_id":"item_nested_1","output_index":0,"content_index":0,"text":"你好！有什么我可以帮助你的吗？"}
+
+data: {"type":"response.output_item.done","item":{"id":"item_nested_1","type":"message","role":"assistant","status":"completed","content":[{"type":"output_text","text":"你好！有什么我可以帮助你的吗？"}]}}
+
+data: {"type":"response.completed","response":{"id":"resp_nested_1","object":"response","status":"completed","output":[{"id":"item_nested_1","type":"message","role":"assistant","status":"completed","content":[{"type":"output_text","text":"你好！有什么我可以帮助你的吗？"}]}],"usage":{"input_tokens":15,"output_tokens":12}}}
+
+data: [DONE]`
+
+	count := countOpenAIImageOutputsFromSSEBody(sseBody)
+	if count != 0 {
+		t.Errorf("expected 0 images for nested sub2api text-only response, got %d", count)
+	}
+}
+
+func TestOpenAIImageOutputCounter_JSONResponse_TextOnly(t *testing.T) {
+	// Simulate JSON response (non-streaming) for text-only message
+	jsonBody := `{
+		"id": "resp_json_1",
+		"object": "response",
+		"status": "completed",
+		"output": [
+			{
+				"id": "item_json_1",
+				"type": "message",
+				"role": "assistant",
+				"status": "completed",
+				"content": [
+					{
+						"type": "output_text",
+						"text": "Hello!"
+					}
+				]
+			}
+		],
+		"usage": {
+			"input_tokens": 10,
+			"output_tokens": 5
+		}
+	}`
+
+	count := countOpenAIResponseImageOutputsFromJSONBytes([]byte(jsonBody))
+	if count != 0 {
+		t.Errorf("expected 0 images for text-only JSON response, got %d", count)
+	}
+}
+
+func TestOpenAIImageOutputCounter_DataArray_FalsePositive(t *testing.T) {
+	// Test: SSE events in /v1/responses should NOT have a "data" array field,
+	// but if one is present with actual image URLs, it should be counted.
+	// The bug was that addDataArray counted ALL array elements without checking
+	// if they contained actual image output (url/b64_json).
+	//
+	// Test 1: data array with non-image objects should NOT count
+	sseWithNonImageData := `data: {"type":"response.completed","response":{"id":"resp_1","output":[{"id":"item_1","type":"message","role":"assistant","status":"completed","content":[{"type":"output_text","text":"Hello"}]}]},"data":[{"id":"not_an_image","status":"done"}]}
+
+data: [DONE]`
+
+	count := countOpenAIImageOutputsFromSSEBody(sseWithNonImageData)
+	if count != 0 {
+		t.Errorf("expected 0 images for data array without image output, got %d", count)
+	}
+
+	// Test 2: data array with actual image output should still count correctly
+	sseWithImageData := `data: {"type":"response.completed","response":{"id":"resp_1","output":[]},"data":[{"url":"https://example.com/img.png"}]}
+
+data: [DONE]`
+
+	count2 := countOpenAIImageOutputsFromSSEBody(sseWithImageData)
+	if count2 != 1 {
+		t.Errorf("expected 1 image for data array with image URL, got %d", count2)
+	}
+}
+
+func TestOpenAIImageOutputCounter_JSONResponse_DataArray_FalsePositive(t *testing.T) {
+	// Test: JSON responses in /v1/responses should NOT have a "data" array field.
+	// But if one is present with non-image objects, it should NOT cause false counting.
+	jsonWithNonImageData := `{
+		"id": "resp_1",
+		"object": "response",
+		"status": "completed",
+		"output": [
+			{
+				"id": "item_1",
+				"type": "message",
+				"role": "assistant",
+				"status": "completed",
+				"content": [{"type": "output_text", "text": "Hello"}]
+			}
+		],
+		"data": [
+			{"id": "not_an_image", "status": "done"}
+		],
+		"usage": {"input_tokens": 10, "output_tokens": 5}
+	}`
+
+	count := countOpenAIResponseImageOutputsFromJSONBytes([]byte(jsonWithNonImageData))
+	if count != 0 {
+		t.Errorf("expected 0 images for data array without image output, got %d", count)
+	}
+
+	// Test: data array with actual image output should still count correctly
+	jsonWithImageData := `{
+		"id": "resp_1",
+		"object": "response",
+		"output": [],
+		"data": [
+			{"url": "https://example.com/img.png"}
+		]
+	}`
+
+	count2 := countOpenAIResponseImageOutputsFromJSONBytes([]byte(jsonWithImageData))
+	if count2 != 1 {
+		t.Errorf("expected 1 image for data array with image URL, got %d", count2)
+	}
+}
+
+func TestOpenAIImageOutputCounter_PassthroughSSEToJSON_Conversion(t *testing.T) {
+	// Simulate the scenario in handlePassthroughSSEToJSON where extractCodexFinalResponse
+	// successfully extracts the response JSON, then countOpenAIResponseImageOutputsFromJSONBytes
+	// is called on the extracted response object.
+	//
+	// The extracted response is just the "response" field from the "response.done" event.
+	// This should NOT have a "data" array.
+	extractedResponse := `{
+		"id": "resp_extracted_1",
+		"object": "response",
+		"status": "completed",
+		"output": [
+			{
+				"id": "item_ext_1",
+				"type": "message",
+				"role": "assistant",
+				"status": "completed",
+				"content": [{"type": "output_text", "text": "Hello"}]
+			}
+		],
+		"usage": {"input_tokens": 10, "output_tokens": 5}
+	}`
+
+	count := countOpenAIResponseImageOutputsFromJSONBytes([]byte(extractedResponse))
+	if count != 0 {
+		t.Errorf("expected 0 images for extracted response JSON, got %d", count)
+	}
+}
+
+func TestOpenAIImageOutputCounter_AddDataArray_FromVariousSources(t *testing.T) {
+	// Test various JSON payloads that might trigger addDataArray
+	tests := []struct {
+		name     string
+		json     string
+		expected int
+	}{
+		{
+			name: "standard response.done event",
+			json: `{"type":"response.done","response":{"id":"r1","output":[{"type":"message","id":"m1","content":[{"type":"output_text","text":"hi"}]}]}}`,
+		},
+		{
+			name: "response with null data field",
+			json: `{"type":"response.done","response":{"id":"r1","output":[]},"data":null}`,
+		},
+		{
+			name: "response with empty data array",
+			json: `{"type":"response.done","response":{"id":"r1","output":[]},"data":[]}`,
+		},
+		{
+			name: "response with single-element data array",
+			json: `{"type":"response.done","response":{"id":"r1","output":[]},"data":[{"url":"https://example.com/img.png"}]}`,
+		},
+		{
+			name: "image_generation.completed event without result",
+			json: `{"type":"image_generation.completed","item":{"type":"image_generation.completed","id":"call_1"}}`,
+		},
+		{
+			name: "output_item with empty type",
+			json: `{"type":"response.output_item.done","item":{"id":"x1","status":"completed"}}`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			counter := newOpenAIImageOutputCounter()
+			counter.AddSSEData([]byte(tt.json))
+			count := counter.Count()
+			t.Logf("  count=%d (maxDataCount=%d, count=%d)", count, counter.maxDataCount, counter.count)
+		})
+	}
+}
+
+func TestOpenAIImageOutputCounter_AddJSONResponse_Exported(t *testing.T) {
+	tests := []struct {
+		name string
+		json string
+	}{
+		{
+			name: "standard /v1/responses JSON response",
+			json: `{"id":"r1","object":"response","output":[{"type":"message","id":"m1","content":[{"type":"output_text","text":"hi"}]}],"usage":{"input_tokens":10,"output_tokens":5}}`,
+		},
+		{
+			name: "response with data field (like /v1/images/generations)",
+			json: `{"id":"r1","object":"response","output":[{"type":"message","id":"m1","content":[{"type":"output_text","text":"hi"}]}],"data":[{"url":"https://example.com/img.png"}],"usage":{"input_tokens":10,"output_tokens":5}}`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			count := countOpenAIResponseImageOutputsFromJSONBytes([]byte(tt.json))
+			t.Logf("  count=%d", count)
+		})
+	}
+}
\ No newline at end of file