I have an 6MB SVG image in my SVG folder and it took over half an hour to show the preview on my P800! It is even slow, if I browse some bigger PNGs. If you worry about not being up to date you can compare the timestamp in the thumbnail with the file date. And no, I don't think that thumbnails are garbage, as long as all programs use the same.
Well, 6Mb is not what I would call typical. Half an hour sounds like a lot. How long does it take to actually open that file?
On a 450MHz Windows machine that I tested, it works quite acceptably for SVG files of average size and complexity (up to several hundred Kbytes). I'm not saying using stored previews is not an option; I'm just saying that the current code works quite acceptably for the average user, so implementing an alternative is not a priority (though of course I would not object if someone develops and commits it).
I'm just speaking about the preview area. It has the "Preview" title,
Which is rather redundant IMHO, especially being so button-looking - is it actually clickable? what does it do? why does it have a keyboard accelerator?
What we actually need is a checkbox or an expander triangle to turn the preview on or off.
some space around the image
Which is confusing - I want the preview to match the actual look, without having to guess if this margin an actual part of the file or not
shows the file size
Which is good, but properly belongs in the file list as a separate sort-able column, not in the preview (by the way, Bob, can we add the filesize column to the list?)
and displays a folder icon, if you are an a folder an not on an image.
It might make sense to borrow that one.