@ batu544,
This Mod sure has taken a life of its own. Everyone has come up with some pretty neat additions to it, this one also...
let me answer the 2 question first, I do not know anything about .htaccess files, my provider does not support them so I have not looked into them. Hopefully someone else can help you there. The only thing that they may have a hard time would be knowing the multi_down_select=8 is equal to 1280X800. good luck on that one.
the other request, yes, it should be possible. I can make it do a formula on the image to gets its ratio and only display sizes that fall into the same ratio. The only downside to that would be if you/or a user uploaded an image that was 1280X799 instead of 1280X800 then none of the selections would match. The sizes would have to be an exact ratio match.
Another way that I may be able to do would be to allow only certain groups to be available depending on the category they are in.
In other words, you would have a wide screen category and only be able to use sizes in group3 and another category for group1 and then those options would be the only ones available. I may be able to make it so you can choose more then one group per category, like group2 and 3 for a category.
My question would be, would it be better to do this image by image or by category?
I have some other things on my plate but will play with the mod some more to see what I can do,
I added a poll to this thread if everyone can choose which way they would prefer it to work...