Have you tried uploading pictures to Friendster or Yahoo Photos and ended up with an error message saying the file size exceeded their limit? My guess is that the picture file you are uploading is a picture you took with your high mega-pixel camera which is more than 1 mb in size. You need to resize it first before you can upload them easily to sites on the net.
The question is how. I do it using Photoshop. You open the picture file. On the main menu, click on Image. Then, on the drop-down menu, click on Image Size. A dialog box will then open. First, make sure that the box before "Constrain Proportions" is checked. Then change the width in Pixel Dimensions to 640. Notice that the height also changes in proportion to the new width. Click on OK.
We're not finished yet. On the main menu again, click on file. On the sub-menu, click on "Save for Web". A dialog box will open with a view of your pic. On the right, choose "JPEG High" for Settings and check the box before "Optimized". Then, click on save. My suggestion is that you save the file with a new file name and on a different folder.
You now have a reduced version of your picture that you can upload easily to say Friendster or Yahoo Photos. Clue, if you're not a techie like me, just follow the steps blindly and ignore all the other options you see along the way. The important thing is that you get the task done. :)
By the way, take note that I am using Photoshop 7.0 with settings at default. There may be command variations for other versions of Photoshop.