Preserve fileformat

[smileychris]

Preserve fileformat

[SmileyChris]

One issue here is that I'm not keen on downscaling indexed images and keeping them indexed - antialiasing may be introduced that looks rather bad due to the limited index.

However I do see the usefulness of the transparency use case. Perhaps the thumbnailing method should check for both png and jpg versions of the thumbnail, and the correct thumbnail format should be generated depending on whether there is a transparency layer.

[ojii]

Well just to be clear, I'm not just talking about png/jpg, what about all the other formats? An option to keep the current format is really the best I can think of. If you thumbnail images with an alpha layer the jpg output is terrible (I think it puts black into the transparent regions). And if you turn all your images to pngs they get huge.

[SmileyChris]

So is the real issue just about preserving the alpha layer as opposed to preserving the file format?

[ojii]

well as a matter of fact I'd argue it's both. Since preserving the file format is more general and goes beyond solving the jpg/png issue I have.

[Soviut]

Agreed. By default the image format should be maintained, be it PNG or JPEG (even GIF if possible, though I see issues with animated GIFs potentially making this difficult) and also provide an option to explicitly convert the thumbnail to a different format at the tag level.

[SmileyChris]

Yep, all that functionality has now been done.