When you're posting in your condo; go down to the 'Upload a File' button and click on a photo. It can only be a zip, txt, pdf, png, jpg, jpeg, jpe, gif, xls, xlsx, ods
So you'll need to make sure your file is saved as one of those formats. I typically save mine as .jpg files. Then once you've got it there - you'll see an option to leave it as a thumbnail or click for 'full image'. Make sure your cursor is in the condo where you want the photo to show up, and click 'full image'...it should appear in the window of your condo.
Are you using a laptop/computer OR your cell phone to post your condo each day?