Formats and output
Supported formats
Section titled “Supported formats”| Format | Open as input | Save as output | Notes |
|---|---|---|---|
| PNG | Yes | Yes | Quality 100 is lossless. Lower values use palette compression. |
| JPEG | Yes | Yes | Quality controls lossy compression. |
| WebP | Yes | Yes | Quality controls lossy compression. |
| AVIF | Yes | Yes | Quality controls lossy compression. |
| BMP | Yes | No | BMP is input-only. |
| GIF | Yes | Yes | Quality controls the available output colour palette. Animated input becomes a static first frame. |
Choose the output format
Section titled “Choose the output format”The output selector sets the preferred format for the preview. The extension uses the filename extension selected in the Save As dialog for the final saved file. Pick PNG, JPEG, WebP, AVIF, or GIF there; BMP cannot be used for output.
Quality and target size
Section titled “Quality and target size”Quality accepts whole numbers from 1 to 100. For lossy formats, lower values usually reduce output size while reducing image detail. PNG and GIF use quality differently, as noted in the table.
An optional maximum size accepts a value such as 500 KB or 2 MB. The extension lowers output quality to attempt that limit. It reports a failure when the limit cannot be reached without going below the available quality range.
Save As protection
Section titled “Save As protection”The Save As dialog requires a different file path from the source. This keeps the original image unchanged while you compare the output result.