If you don't have any webspace of your own, host the photos on a free hosting site like imageshack or photobucket. Then use the linking code they provide to post a thumbnail image here.
Both those services will have their own file size limits but they're pretty generous. If it's still a problem, use any photo editing software to resize the image before uploading.
Best of luck!
If you do use imageshack, their free toolbar make uploading and linking multiple images very quick and easy. Some people complain imageshack has too many pop-ups or is slow - I don't find that myself and find it very user friendly, but your mileage may vary. Photobucket is very popular and highly rated.