Are you trying to add a photo to a cache page for which you are the cache owner?
If that is the case, here are the steps:
1. In the box in the upper right hand corner of your cache page, click upload images
2. View gallery (either immediately, or from that same box on the main page)
3. Right click (right mouse button) on your image and select view image
4. Copy the URL for your image
5. In the box in the upper right hand corner of your cache page, click Edit listing
6. Make sure the HTML button is checked and insert the following code:
<img src="URL That you obtained in step 4">
You may use any standard HTML code to change things like the size, location (e.g. centering), etc.
Good luck.