well nomatter what program you use it still would make the same file types. Which means the same size pictures
Not sure I understand but maybe Fauxto.com?It's like online photoshop though it's kinda hard to use and you won't get as nice effects. If you want something a bit better I would suggest GIMP, it's weaker then photoshop but it gives good results for general photo editing, though I am not sure how much hard drive space it takes up.
<span style="font-family:Comic Sans MS">Adobe is actually making a Photoshop version that runs strictly from the browser..........it'll have less features but it's mainly for basic photo editing http://blogs.adobe.com/jnack/2007/09/photoshop_expre.html</span>