How can I post a photo to instagram that was on my computer and not taken from my iPhone? I want to use a photo from my computer and put it on my instagram account. The problem is that when I go to choose the picture, its not shown in the list of images in the /DCIM/100APPLE folder. I believe the issue is that it doesn't have all of the meta data about how the picture was taken so the software doesn't show it.

Someone has said that you need iTunes to do anything on your phone but I'm running linux and iTunes isn't available for my operating system.

Is this the only option? What can I do?
Send the photo to yourself
Save it to camera roll from the mail you just sent to yourself. 
Post it on instagram 


That's it ;)