Compare the original and one real conversion result
This workspace places the original and the result of the same conversion together. Move the comparison divider to inspect each side, or switch to a side-by-side display. It is useful for checking text screenshots, photographic textures, icon edges and transparent areas. It does not assign a universal quality score. Acceptable appearance depends on the image purpose, viewing distance and actual display size.
Keep dimensions equal when you want to compare compression settings separately from resizing. When width or height changes, both pictures may be placed in the same comparison area even though their pixel detail differs. You can open the original or output for a closer browser view. The comparison divider changes only the display; it does not alter the generated download or combine both pictures into a comparison file.
Worked example
Generate a WebP from a 160 by 100 PNG with the same dimensions and compare the edge of a small label. A lower quality may change that edge even if a large flat area looks similar. Moving the divider does not re-encode the file. Changing quality or dimensions invalidates the old result, so generate again before evaluating the new setting.
Local processing and limits
One supported static image is processed at a time. The general input limit is 10 MiB and twelve million pixels; AVIF processing is limited to four million pixels. Unsupported animation, image sequences, HDR and unverified container features are refused. Large images need more memory even when their compressed file is small. A failed operation does not switch to a server-upload fallback.
The browser downloads its own application and codec resources from the same host. Your selected image, result, filename and metadata are not sent to an upload service. Images are not written to localStorage, IndexedDB or a service-worker recovery cache. Reloading the page leaves the image workspace empty. Downloaded files remain under your control; inspect them before sharing.