Ok Scott, here's what you need to do.
Option #1 - Open the file where the picture is stored and right-click on it. Select "open with" and "MS Office Picture Manager" (if you don't have Office, use option #2). From the top menu select "edit pictures" and "crop" if you need to remove any background. If not, choose "resize" and choose option "predefined width x height:" and then "Web - Large (640 x 480)" and then the "OK" button. Remember to "save as" a new file name ... I usually just add an 'x' to the end. This will retain your original file as is. Close picture mgr and go to the new file you just resized. Right click on it and view "properties". The key is that it needs to be less than 100 kb. For grading and variety attribution, they need to be as close to 100 kb as possible. If the new file is between 90~100 kb, you're good to go. If not, go back to the original file and start again ... there's another option in the "resize" window. "percentage of original". Try this option to get as close to 100kb as possible. Always remember to save the trial picture with a different name than the original.
Option #2 - Right click on the file and select "open with" and then "paint". From the top menu bar click on "image" and then "attributes". From the upper "stretch" option you can enter a new % of height and width (always enter the same % in each box) and then hit "OK". Save the new sized file with a different one from the original. Open it and check the new size (right click, "properties"). You may need to experiment here to get the file between 90~100 kb.
One final note ... each time you resize, start with the original (delete the experiments). You'll lose critical resolution if you continue to modify copies.
Good luck.
So many coins, so little time ...