Sooo I started an Instagram page and for the life of me can't work out the best way to upload digital artwork without taking a pic of my computer screen or a screenshotting the work on my phone... I'm afraid this might be a really dumb question but it's out there now lol
I'm on Android, so this may be different on IOS, but I click on the photo button and there's three tabs at the bottom: *Gallery*, *Photo* and *Video*. With the *Gallery* tab selected, there's a dropdown at the top that defaults to *Gallery*. I open that up, select *Other*, then click on *Dropbox*.
That's mainly how I transfer images onto Instagram. Chuck 'em onto dropbox then access them in Instagram via the above method. Videos too.