Conversion without the upload.
Traditional converters send your image to a remote server, wait for processing, then send a new file back. FormatSprout skips that round trip.
1. Your browser reads the image
Modern browser APIs decode the selected JPG, PNG, or WebP file in local memory. The file never becomes an HTTP upload.
HEIC and HEIF use a decoder downloaded to your browser when needed. AVIF uses native decoding where available, with a downloaded decoder as a fallback. Downloading these tools does not upload your photos.
2. A fresh image is rendered
The image is drawn onto a temporary browser canvas at the requested dimensions. JPG exports receive a white background; PNG and WebP can keep transparency.
AVIF export uses a local encoder rather than the browser’s built-in canvas export. It can take longer than JPG, PNG, or WebP. ZIP downloads also load a local packaging library on demand. The first use of these features needs a network connection to download the code.
3. The browser exports your result
The canvas creates a new file in your chosen format. This also strips embedded EXIF metadata. FormatSprout creates a temporary download link and releases it when no longer needed.
Compatibility and limits
A current version of Chrome, Edge, Firefox, or Safari is recommended. Animated files are converted from a single still frame. Each input is limited to 50 MB and decoded images to 40 megapixels to protect device memory.
What stays, and what changes
Resizing is optional. With resizing blank, the output keeps the decoded image dimensions. PNG encoding adds no lossy compression to the rendered pixels; JPG, WebP, and AVIF outputs use quality settings. This is not a color-managed archival workflow: embedded profiles, HDR information, depth maps, and Live Photo motion are not preserved.
Verify that your images stay local
Open your browser’s developer tools and its Network panel before converting a non-sensitive sample. You may see page assets, decoder downloads, and limited analytics requests. There should be no image upload. JPG, PNG, and WebP conversions can run after the page has loaded even if you disconnect; on-demand codecs and ZIP packaging must be loaded before using those features offline.
Analytics records usage counts and performance, not image contents or filenames. You can exclude your visits from analytics in the privacy settings.
If something goes wrong
- Wrong format: use the converter for your source file, or choose the all-format converter below.
- Large image: the 40-megapixel limit applies to the decoded image, even if the compressed file is under 50 MB.
- HEIC or AVIF stalls: keep the tab open, try one image first, and check your connection for the initial decoder download.
- ZIP fails: download the finished images individually or try a smaller batch.