File Compression...

I don;t know what to call it, but I need to know if it's possible, and if it is, then how, to do this:

Say I have a complex JPG image, or GIF, but it's a big file, is there any way to lesson the size, but keep the quality?

Thanks.

If it's that big of a file I would just save it at a lower quality. Oppose to saving a Jpeg file at 100% quality save it at 75% quality, which should lower the file size a bit. other than that I don't know how.

EDIT: Didn't read that you wanted to keep the quality. There isn't that big of a difference between 75% and 100% quality so if you want to try my suggestion then go for it.

I'v herd that PNG is the best file. ^^

Actually, Jaden, PNG and BMP have exactly the same quality. PNG compresses it, however, whereas BMP doesn't.

Jpeg is lossy compression - it degrades the quality of the image in a certain way to make the filesize smaller. This, however, is usually rather terrible, and using a jpeg for anything is pretty much always a really bad idea.

Gif is lossless compression, however it is restricted t 256 colours, rather than the 16777216 colours of jpeg, png and bmp.

Bmp has a huge filesize. Don't use it.

I personally recommend Png. It retails all quality, and depending on the image, will usually be pretty small. Png is exceptionally good for screenshots and things, as screenshots usually consist of large blocks of colour. If you have an image where everything is a huge mess of differrent colours (like a sig, photo, etc), then saving it as a 100% quality Jpeg usually retains all the quality. If you're willing to compromise quality just a little bit, then saving the image in Photoshop as a Jpeg with 10/12 quality can be ok. I wouldn't recommend going lower than 10, though.

Yes PNG is the best for image quality at such a small file size.