JPEG image with alpha channel on website [closed]

Answer 1

JPEG doesn't support transparency. You'll need to stick to PNG or GIF. Why do you want to use a JPEG for transparency?

Update

Please disregard this answer, it was written back when Canvas support was sparse. Refer instead to martin's answer.

Answer 2

You cannot have any kind of transparency with a JPEG image : JPEG doesn't support that.

You can switch to PNG images, to get either 1bit or 8bits of transparency (or GIF, which only supports 1 bit -- i.e. transparent, or not-transparent).

You can also switch to WebP which has similar mechanics to JPEG. It supports lossy/lossless compression, transparency and animations.

Answer 3

The original JPEG format doesn't provide for an alpha channel. You can make a PNG file, however. It will work in IE7+ and other "modern" browsers.

The "JPEG 2000" format does support transparency, but despite the name it's really a completely new image encoding format. It's only supported by Safari.