how to compress jpeg to reduce size

[Thierry de Coulon]

On Saturday 05 February 2011 11:37:59 pm Tapas Mishra wrote:
> I have an image which is 1.7Mb in size it is a scanned document.
> I have to submit it online in an application where they do not accept
> more than 1 Mb size JPEG
> so how can I reduce the size of this image.Any format other than this
> gif,png,jpg also is acceptable but
> file size should be 1 Mb only.So how can I achieve this let me know if
> some one has any suggestions for the same.
>
> --
> Thanks

Correct me if I am wrong, but:
- jpeg _is_ compressed nearly as much as possible, so you can't compress it 
more (trying to usually results in a bigger file, actually)
- jpeg is a lossy compression, so you can decrease the image size by 
decreasing the quality (Gimp lets you set this when saving a jpeg). You get a 
smaller file but a worse quality.
- you can reduce the size of your picture (less pixels, less size) or the 
color depth.
- you can combine all these options

The best option depends on what you want to do with the picture.

Gif is usually best for drawings with solid colors.
I don't think that PNG has any size advantage, but you can save images with 
transparency (alpha channel), what jpeg can't as far as I know.

Hope this helps,

Thierry