[wulf]

The image size depends on the dimensions, the content of the picture, the file format and how much it is compressed. Complicated, eh?

If your longest side is 600px and the other side is also getting on for 600px, that's up to 360,000 little dots that the file has to store information about. In a complex picture with minimal compression that could result in quite a large file.

Assuming that you're using JPG files, the solutions are to either go for smaller dimensions (the Flickr medium size is 500px on the longest side and you might even be able to push it down further than that) or to increase the level of compression (try a few different levels and take a look to see how much you can get away with). At a compression level of 85 (1 being squashed into oblivion and 100 being uncompressed), I regularly find that pictures of 600px+ on the longest side come in at less than 100KB.

Or upload the pictures to Flickr and set them to private. We won't be able to browse over there to see the full sized version but we will be able to see the image (the same probably applies to other photo sharing sites as well).

Wulf