Save Image as Format per Maria

A Firefox WebExtension that adds an image context-menu item named Save image as format.

To use it, just right click on an image, and find the "Save image as format" button, and select the file type!

The conversion happens on your device in the extension background page, so no data is sent anywhere. The extension fetches the selected image, decodes it in Firefox, draws it to a canvas, converts it to the chosen output format, and starts a normal Firefox download prompt.

I (codex) made this extension because I was tired of downloading corrupted images, or having to use web converting sites and downloading the image multiple times, blah blah blah... so I came up with this to solve my problems!

Formats

• PNG
• JPEG
• WebP
• GIF
• AVIF
• BMP

JPEG, GIF, and BMP do not support full alpha transparency, so transparent pixels are flattened onto white (#FFFFFF).

Animated images are saved as the first decoded frame because browser canvas export is still-image based. GIF export creates a single-frame GIF. AVIF export uses Firefox's built-in canvas encoder and will show an error if the current Firefox build does not support image/avif export.