Adobe should be very easy. You should be able to go up to the tab called image, and click on resize. then you can change the size pixels. Look under all of the little titles for the word RESIZE. Once you find the resize feature then you can put in the size that you want the picture to be. then you can re-save it, and post it on the board. I have not used adobe in a while, but i think that is how you do it. If not let me know, and I will figure it out.
HTH
Leopard