Follow these instructions to reduce your image size:

1. Click "Start" --> Go to "Programs" and then "Accessories" ---> Click on "Paint"
2. Open the file you want to post.
3. Click on "Image" in the toolbar and pick "Stretch/Skew"
4. You can reduce the size of the image down to 50% for both settings.
5. Click "File" and go to "Save As". You don’t want to save over the original because you want to keep it at the larger size. Pick a new file name to save you new image and go ahead with the save.

Then go to the image and right click with your mouse. Choose properties and see how large the image is. If it is still larger then 100kb, then you need to reduce the percentage lower then 50 as mentioned in step 4. If you take photos with a 5 mega pixel camera then you will probably need to type in a percentage of around 20% for the vertical and horizontal stretch.