A 800-wide photo may look quite large, there could be several different reasons for that. Two of them are, different screen resolutions and your Windows screen magnification settings.
Some have said they resize their own photos. You can do that with Irfanview -
1. File > Batch Conversion/Rename.
2. Make sure Output format is in JPG/JPEG Format
3. Look for the Advanced button.
4. Look for the Resize section of the menu. (left)
5. Resize the photo(s) by setting the width.
- Click image to see larger view
-- As long as it's 800-width it's good to post. It may be large on some screens. However, play with those numbers to see what size you like best.