Why does a transparent background turn white after converting to JPG?

JPG stores only 3 color channels and has no 4th alpha channel, so every transparent pixel must be filled with a solid color, which defaults to white, #ffffff. Pick a different color in the transparency fill option if white does not suit your layout. To keep the transparency itself, convert to PNG, WebP or AVIF instead, since all three formats can store an alpha channel alongside the color data.

Can I convert iPhone HEIC photos to JPG here?

That depends on whether your browser can decode HEIC. This page bundles no HEIC decoder and relies on the browser, which today usually means Safari; Chrome and Firefox report that the file cannot be decoded. Alternatively, set the iPhone camera format to Most Compatible, or export the photos as JPG first, then process them here in batches of up to 30 files, each at most 50 MB.

Is WebP at quality 100 lossless when converting from PNG?

In Chromium browsers such as Chrome and Edge, yes: in our test, WebP at quality 100 decoded back with a pixel difference of 0, while any setting below 100 uses lossy encoding. Other browsers ship different encoders, so verify the result or keep PNG when you need guaranteed lossless output. JPG is never fully lossless here, and even quality 100 showed small pixel differences in the same test.

Image format converter

Batch-convert between JPG, PNG, WebP and AVIF locally, with quality and transparency fill settings

Computed in your browser

Choose a target format, then drop or choose images. Changing the format, quality or fill color reconverts automatically; download single files or a ZIP when done.

Choose or drop images You can also paste an image from the clipboard. Images are processed in this browser and never uploaded. JPG, PNG, WebP, AVIF, BMP, GIF, ICO, plus HEIC/TIFF where the browser can decode them; up to 30 files, 50 MB each.

Convert to

Quality 90

Fill for transparency (JPEG)

Example

Input

sample.png (generated, 1200×800) · convert to JPG · quality 90

Example result

sample.jpg · 1200×800 · JPEG, with sizes before and after and the percentage change

The sample has no transparency, so the fill color has no effect. A transparent PNG converted to JPG shows the chosen color where it was transparent.

Technical details & limits

Inputs are decoded by the browser (createImageBitmap, with EXIF orientation applied). No extra decoder is bundled, so HEIC, TIFF and similar formats load only where the browser supports them natively. Output is encoded with Canvas toBlob: JPG has no alpha channel, so transparent pixels are filled with the chosen color; PNG is lossless and ignores quality; in Chromium browsers, WebP at quality 100 measured a pixel difference of 0. AVIF output depends on the browser and the option is disabled where unsupported. Pixel dimensions are unchanged and EXIF and other metadata are not kept.

About this tool

Batch-convert JPG, PNG, WebP, AVIF, BMP, GIF and other images to JPG, PNG, WebP or AVIF. Adjust quality for lossy formats and choose a fill color for transparency when converting to JPG. Each image shows its format, dimensions and size before and after, with a comparison preview, single downloads and a ZIP bundle. Conversion runs locally in your browser; images are not uploaded.

How to use

Drop, choose or paste images, up to 30 at a time.
Choose the target format; adjust quality for lossy formats and the transparency fill for JPG.
Review the results, then download single files or a ZIP.

Input & output

Input: JPG, PNG, WebP, AVIF, BMP, GIF (first frame), ICO, plus HEIC/TIFF where the browser can decode them; up to 30 files, each at most 50 MB and 50 megapixels.
Output: JPG, PNG, WebP or AVIF files at the original dimensions, downloadable singly or as a ZIP.
Limits: No GIF, ICO, HEIC or TIFF output; no animation; metadata and color profiles are not kept.

Notes

Converting does not restore detail: a low-quality JPG saved as PNG grows larger without regaining lost detail. Use the image compressor to reduce size.

FAQ

Why does a transparent background turn white after converting to JPG?: JPG stores only 3 color channels and has no 4th alpha channel, so every transparent pixel must be filled with a solid color, which defaults to white, #ffffff. Pick a different color in the transparency fill option if white does not suit your layout. To keep the transparency itself, convert to PNG, WebP or AVIF instead, since all three formats can store an alpha channel alongside the color data.
Can I convert iPhone HEIC photos to JPG here?: That depends on whether your browser can decode HEIC. This page bundles no HEIC decoder and relies on the browser, which today usually means Safari; Chrome and Firefox report that the file cannot be decoded. Alternatively, set the iPhone camera format to Most Compatible, or export the photos as JPG first, then process them here in batches of up to 30 files, each at most 50 MB.
Is WebP at quality 100 lossless when converting from PNG?: In Chromium browsers such as Chrome and Edge, yes: in our test, WebP at quality 100 decoded back with a pixel difference of 0, while any setting below 100 uses lossy encoding. Other browsers ship different encoders, so verify the result or keep PNG when you need guaranteed lossless output. JPG is never fully lossless here, and even quality 100 showed small pixel differences in the same test.

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