MARDUK SYNDICATE

WebP to JPG or PNG on Windows: one file, or a whole Downloads folder at once

By Marduk Syndicate Updated 16 Sep 2026

You saved an image and got a .webp that half your programs won’t open. Here’s why, the rule for transparency, and how to convert one file or a folder of them without uploading anything.

Why you keep getting WebP

Websites serve WebP because it’s smaller: Google’s own FAQ says WebP “typically achieves an average of 30% more compression than JPEG”. When you use Save image as, the browser saves the bytes it received, so you get the format the site chose. The why Chrome saves images as WebP page explains the mechanism.

Whether Windows itself opens WebP depends on an optional Microsoft Store package being present, which is why Explorer thumbnails come and go between PCs. Simple Image Converter carries its own WebP decoder, so it doesn’t matter.

Transparency: PNG keeps it, JPG fills it

WebP can carry an alpha channel (Google’s FAQ: “WebP supports 24-bit RGB color with an 8-bit alpha channel”). JPG can’t. So the rule when converting a logo or a cut-out is:

  • WebP → PNG keeps the transparency.
  • WebP → JPG flattens it onto a background colour, which you should choose on purpose.

We tested it on 16 Sep 2026 with a WebP containing a rounded panel on a transparent background:

WebP → PNG · transparency kept
A teal rounded rectangle reading 'alpha test' on a transparent background, saved as PNG; the page background shows through around it
WebP → JPG · flattened on white
The same teal rounded rectangle saved as JPG, now sitting on a solid white background
The same WebP converted both ways. The PNG (left) keeps the alpha channel; the JPG (right) had to be flattened, here onto white. Simple Image Converter lets you pick the background colour for JPG output.

For photos, none of this applies: a WebP photo has no transparency and JPG at quality 90 is the right target. In our test, a 2,048-px WebP photo of 581 KB became a 1.05 MB JPG at quality 90 and a 4.6 MB PNG. PNG is a poor choice for photographs; the app’s Web images → PNG preset is for graphics and screenshots, and JPG is one click away for photos.

One file or a folder, the same way

Drop the file, or the whole Downloads folder, onto Simple Image Converter. Click Web images → PNG, or choose JPG and a background colour, then Convert All. It converts in parallel, skips files it can’t read with a reason, and never overwrites: a name clash becomes name_2.png. It decodes WebP and AVIF as well as HEIC, so a mixed folder is one pass. In our timing, 12 WebP photos converted to JPG in 0.13 seconds and to PNG in 2.3 seconds on an 8-core desktop using the app’s decoding library.

Simple Image Converter
Simple Image Converter with eight WebP, JPG and HEIC files queued, the Quick presets panel, JPG output at quality 90 and the Strip metadata switch on
WebP, JPG and HEIC queued together. The Web images → PNG preset sets PNG output; JPG output has a background-colour setting for transparent images.

It saves JPG, PNG, WebP (lossy or lossless), TIFF, BMP, ICO and PDF, and it runs offline on Windows and SteamOS/Linux with no upload and no daily cap. One-time purchase on Steam.

Get Simple Image Converter on Steam