It looks like your rear diff has leaked a small amount of gear oil, but the presence of fresh oil at the bottom of the diff cover is somewhat troubling. You have a few options:
1. Attempt to tighten the bolts. It may not completely stop the leak, but it may slow it down and at least you will know if your bolts were loose.
2. Inspect the fill plug, as was mentioned above. Replace as necessary.
3. Take it to a mechanic and have your rear Chrysler 8.25" differential fluid changed. This will cost you 5 times the amount than it would if you do it yourself, but at least you'll know you helped a semi-skilled mechanic make his car payment this month.
4. Buy the required amount of diff fluid (4.8 pints of 75W-90 gear oil), 2 ounces of limited slip additive, and a tube of RTV sealant. Attempt to change the fluid and reinstall the cover yourself.
5. Buy the required amound of diff fluid (see above) but instead of RTV, order a Lube Locker (
www.lubelocker.com) for your 8.25" rear diff and use that in place of the RTV sealant. That Lube Locker is reusable, simple to install, and approximately $15, plus shipping.
6. Do nothing except put a piece of cardboard beneath your leak and save the planet from a few drops of differential fluid. I've done that for months.
Hints: Ensure you torque your bolts in the proper order, and with the proper torque values. Don't attempt this simple procedure if you are not familiar with "righty-tighty, lefty-loosey" or your complete collection of tools includes one small claw hammer for hanging pictures and a tape measure.
Good luck.