Convert a mixed image batch
Drop images, choose one output format, and download each converted file or the whole batch as a ZIP. The queue shows the stage for each file, including reading, queued, converting, adding to ZIP, and done.
The converter is built for folders that contain mismatched sources: screenshots, CMS exports, phone images, design exports, and favicon candidates. Format conversion changes the encoded file type; it is not the same as renaming an extension.
Output format choices
Use WebP for website images when smaller files matter and the publishing target accepts WebP. WebP supports lossy compression, lossless compression, and transparency.
Use AVIF when file size matters more than encode time. AVIF can compress photos very well, but large exports can take longer on the same device.
Use JPEG for photos when transparency is not needed and the output must open in older software or broad sharing contexts. JPEG is lossy and cannot store transparency.
Use PNG for screenshots, UI graphics, logos, and images that need an alpha channel. PNG preserves hard edges well, but it can produce larger files for photos.
Use GIF only when the target specifically needs GIF output. It is a compatibility format, not the best choice for full-color still images.
Use ICO for favicon files. The converter caps oversized ICO output at 256px on the longest side.
Transparency and metadata
PNG, WebP, AVIF, and GIF can carry transparency in different ways. JPEG cannot, so transparent pixels have to be flattened when the output is JPEG.
Metadata is treated differently from pixels. When the browser decodes an image and the worker re-encodes it, EXIF, GPS, camera model, orientation tags, and embedded color profiles are commonly removed. Archive the source files separately if that information needs to survive.
Large batches
Batch conversion still depends on the current tab, the browser, and the device. Very large TIFF files, phone HEIC photos, high-resolution AVIF exports, and hundreds of files can use enough memory to slow or fail the job.
For large folders, process smaller groups and check the downloaded output before deleting originals.
Conversion pipeline
The conversion worker tries native browser paths when they fit the target format. OffscreenCanvas can encode common web outputs without blocking the main UI thread.
When native decoding or encoding is not enough, the worker falls back to ImageMagick compiled to WebAssembly. That heavier path adds support for formats that plain browser image APIs do not handle consistently, such as HEIC, TIFF, PSD, and some camera-originated files.
ZIP packaging happens after conversion, so the archive contains the finished files rather than the original sources.
Format-specific pages
The related converter pages lock the input and output pair, such as WebP to PNG or PNG to JPEG. Use the full converter when one batch needs a single output format from mixed sources. Use a focused page when the task is already known.