Decrease the bits of your pictures!
Remember back in the good old days when new displays first came out with 24-bit True Color? Well now you can go back to _before_ the good old days!
Ideas:
-decrease the total number of colors used in your picture
-use in combination with dithering to eliminate banding artifacts
Instructions:
Step 1. Select a picture directly from your camera or gallery
Step 2. Filter your picture with Picture Quantize!
Step 3. Save a copy of your new picture back to your gallery
Step 4. Send your new picture directly to an email or another application