Bug 98971 fixed major issues with image resize. Per bug 98971 comment 146 we could improve image quality, especially PNG images. See attachment 205595 [details] (quality comparison img_resize.html) The resize algorithm used by MSPaint gives a better image than Moz...

Downscaling and upscaling need different algorithms. This one looks like it's using an upscaling algo to downscale.

Downscaling on 2.0.0.4 verified to still use nearest neighbor (or something like it). Note bug 312309 likely a dup of this.

We hit the same issue in TomTom HOME, I am attaching an example. In this case we are resizing a 250x221 image to 60x53. On the left is the result in Firefox 3.0.3 (XULRunner 1.9.1b1 gives identical results) - rest are different resizing algorithms from an image editor. Second from right is "nearest neighbor" which is similar to Firefox but still a lot better.

I report similar bug... https://bugzilla.mozilla.org/show_bug.cgi?id=486918 IMO dev team should implement Lanczos or at last BiCubic resampling for downsizing or upscaling images for the best quaity... This methods is not very heavy for CPU, so it should works for all ppl fine...

You won't help your cause by spamming people. The "blocking" flags are there for a reason (https://wiki.mozilla.org/Calendar:For_Everyone:Blocking_Flags), don't misuse them.

I just tried specifying "image-rendering: optimizeQuality" (https://developer.mozilla.org/en/CSS/image-rendering) in Minefield build 20090807 but I don't see a significant difference. Looks like it doesn't fix this bug.

In Gecko 1.9.2 there is no difference between "optimizeQuality" and "auto" (default value), both use bilinear resampling. Will clarify that in the MDC CSS reference.

Does this bug cover the upscaling quality difference between Mac and Linux (upscaling on Linux is notably worse than on Mac)?

FWIW, on Linux, both Chrome and Opera have nicer image upscaling than Firefox.

Any plans for implementation this in future releases next to Firefox4 ? Because downscaling quality in the worst compared to all other browsers...