How to share my Facebook synced photos from my iPhone?

I have an iPhone 4, and have enabled Facebook's Photo Sync feature. I'm sure I'm missing something obvious here, but I can't seem to find a way to share a photo from my synced folder using my iPhone. The Facebook help page gives instructions for sharing them from my computer, but I rarely access Facebook from my computer anymore.

Here's how I've (unsuccessfully) tried to share a photo: I go to my timeline page, select Photos, and select the Synced button on the bottom right. This brings me to my synced photo thumbnails - so far so good. When I select an individual photo, there's a trash can at the bottom left, and the word "Done" at the top right. If I tap and hold, I'm given the option to save or delete. Neither of these help me. I've also noticed that when I look at the thumbnail page, there are no check boxes on the thumbnails to select.

The reason I'm trying to share synced photos rather than simply upload them to Facebook again (which would just be redundant), is that I'm often in areas where I get poor cell reception, and while I can post messages and updates to Facebook, I often can't successfully upload photos.

There's another option next to the trash can like an arrow coming out of the box. Tap that and you will have options to upload, email, print etc.