| Converted JPG shows a white or black background | JPEG cannot store WebP alpha transparency. | Choose a suitable flattening color or use PNG/WebP when alpha is required. |
| Converted image looks blurry | Quality may be too low or resizing removed detail. | Increase quality, use the source image and inspect output at normal size. |
| WebP output is larger than input JPG | The source may already be optimized or the new quality too high. | Reduce size or quality and compare; retain the source when it wins. |
| Animated WebP becomes a still image | JPEG and regular PNG are static formats. | Use frame extraction or retain animated WebP to preserve movement. |
| Frame extraction is unavailable | The browser may lack a compatible WebCodecs decoder. | Use a supported browser or a dedicated animation utility. |
| Not all animation frames appear | Decode support or file-specific timing/disposal may differ. | Inspect frame count and retry with a compatible browser. |
| File cannot be decoded | Content may be corrupt or format unsupported. | Validate file bytes and re-save to a conventional image format. |
| Format differs from extension | The filename suffix does not match its binary encoding. | Use the analyzer to identify actual contents; do not just rename. |
| Colors look different after export | ICC profile or encoding color interpretation may change. | Compare in a color-managed viewer and keep the original profile-sensitive source. |
| Edges show light halos | A transparent subject was composited onto a mismatched solid color. | Choose a matching background or keep alpha in PNG/WebP. |
| Batch job runs out of memory | Large image dimensions or too many simultaneous operations. | Process smaller groups and close other memory-heavy tabs. |
| Conversion feels slow on mobile | Device CPU and memory limit local processing. | Reduce image dimensions or process on a more capable device. |
| ZIP download contains fewer files | One or more items may have failed conversion. | Inspect per-file job status and retry failed images. |
| Filename has unexpected suffix | Output format or naming settings may differ from expectation. | Verify output direction and resulting MIME type. |
| Metadata disappeared | Re-encoding can strip EXIF or XMP fields. | Preserve the original and inspect metadata settings before export. |
| Location remains in shared image | Other metadata or visible landmarks may disclose location. | Inspect the export independently and crop or obscure identifying visuals. |
| Transparent logo turns solid in JPG | JPEG does not support alpha. | Choose PNG or WebP output for transparent graphics. |
| Tiny text gets artifacts | Lossy encoders can blur sharp edges. | Use higher quality or PNG for small UI and text graphics. |
| Website looks slow despite WebP | Other resources or delivery strategies may dominate LCP. | Audit deployed pages and prioritize actual bottlenecks. |
| CLS score stays poor | Image compression does not reserve layout space. | Set dimensions or aspect ratio for rendered images. |
| Responsive markup loads wrong asset | Srcset paths, width descriptors or sizes may be incorrect. | Check generated URLs and inspect network-selected resources. |
| JPEG fallback does not appear | Picture source ordering or fallback path may be incorrect. | Check the HTML source and actual hosted JPG URL. |
| URL image import fails | CORS, authorization or network access may block source retrieval. | Download an authorized source locally and upload the file. |
| Output quality looks worse after repeated conversions | Lossy encoding damage accumulates after each re-save. | Return to the original master and make one final export. |
| No bytes saved at high quality | Compression settings can preserve more detail than necessary. | Try a slightly lower quality or correct display dimensions. |
| PNG output is much larger | Lossless PNG may use more bytes for photographic pixels. | Use WebP or JPG when alpha and pixel-exact preservation are unnecessary. |
| Some browsers produce different sizes | Native encoder implementations and feature support differ. | Compare files on your production-supported browsers and verify output. |
| Animation contact sheet is blank | Frame decoding or transparency handling may not complete. | Try compatible browser/frame settings and check original animation. |