One of the most common things that people should do, but don’t is down-sample images from their cameras before these:
1. emailing to family or friends
2. uploading them to a web site
This free video shows you how to do it, and below the video are free scripts for both Photo-PAINT X3 and X4. Ensure you use the script applicable to your version (both are in the single ZIP file).
I like to apply 50% adaptive unsharp to images after downsampling, so I put this in the script.
NOTE: You can edit the scripts in Notepad to change the default value of 700 pixels wide to something else if you like.
If you don’t have photo-PAINT, you could use Irfanview. The process is quite different, but the goal is the same & achievable.