Photoshop: sizing an image
Uploading an image to WordPress is nearly the same as uploading a file (covered in the previous topic).
After you’ve corrected the image in PhotoShop
(see: http://peninsulaartists.com/faq/basics/photoshop )
you need to make sure it’s been sized properly.
The following is from the referenced PhotoShop page on this web:


Save for web as .jpg. Use the ctrl-shift-alt-s combination to bring up the “save for web” dialog.
You will be doing two things here: setting the image size in pixels, and setting the jpeg compression. Use 2-up viewing to see the results of image compression (choosing a compressed jpg setting will make the image load faster and look worse).
jpeg compression
The bottom image shows the options on PhotoShop CS3; your screen may look quite different.
I never go lower than 30, and never higher than 80. Remember: gifs are for graphics, .jpgs are for photographs. On image size:
image size
For WordPress, the images will be about 200 to 400 pixels maximum on a side.
For Coppermine, images will be no greater than 700 pixels on a side. 400 is acceptable. Save the results to a separate folder to make uploading really easy.