mudler/LocalAI · error

Failed to load mask image from

Error message

Failed to load mask image from '%s'\n

What it means

The mask image path given for inpainting could not be decoded. Guard: verify the mask file exists, is a supported image format, and matches the input image dimensions before starting the diffusion run.

Solutions

1. Verify the mask image path is correct and the file exists.
2. Confirm the mask file is a valid image in a supported format (PNG/JPEG).
3. Check file permissions on the mask image.

When it happens

Trigger: Thrown at backend/go/stablediffusion-ggml/cpp/gosd.cpp:890 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of mudler/LocalAI@44413a9d06 (2026-08-15). Data as JSON: /api/errors/d2f5da8c9e4e6cc3. Report an issue: GitHub.

Appendix: source

Thrown at backend/go/stablediffusion-ggml/cpp/gosd.cpp:890

        p->init_image = {(uint32_t)width, (uint32_t)height, 3, input_image_buffer};
        p->strength = strength;
        fprintf(stderr, "Using img2img with strength: %.2f\n", strength);
    } else {
        // No input image, use empty image for text-to-image
        p->init_image = {(uint32_t)width, (uint32_t)height, 3, NULL};
        p->strength = 0.0f;
    }

    // Handle mask image for inpainting
    if (has_mask_image) {
        fprintf(stderr, "Loading mask image: %s\n", mask_image);

        int c = 0;
        int mask_width = 0;
        int mask_height = 0;
        mask_image_buffer = stbi_load(mask_image, &mask_width, &mask_height, &c, 1);
        if (mask_image_buffer == NULL) {
            fprintf(stderr, "Failed to load mask image from '%s'\n", mask_image);
            if (input_image_buffer) free(input_image_buffer);
            return 1;
        }

        // Resize mask if dimensions don't match
        if (mask_width != width || mask_height != height) {
            fprintf(stderr, "Resizing mask image from %dx%d to %dx%d\n", mask_width, mask_height, width, height);

            uint8_t* resized_mask_buffer = (uint8_t*)malloc(height * width);
            if (resized_mask_buffer == NULL) {
                fprintf(stderr, "Failed to allocate memory for resized mask\n");
                free(mask_image_buffer);
                if (input_image_buffer) free(input_image_buffer);
                return 1;
            }

            stbir_resize(mask_image_buffer, mask_width, mask_height, 0,
                         resized_mask_buffer, width, height, 0, STBIR_TYPE_UINT8,

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