There was a time when this was not possible. Instagram, now owned by Facebook, started life as an iPhone app. So, if you wanted to upload a photo to your Instagram account, the photo had to be on your iPhone (the app also works on the iPad, but it’s the iOS app).
Mac users with an extensive collection of digital photos in iPhoto or Photos were out of luck. Facebook? Yes. Flickr? Yes. Instagram? Nope.
Now there’s a Mac app which lets you drag and drop to upload photos from your Mac to your Instagram account. It’s called Up – Uploader for Instagram. How Up gets around the Instagram restriction of ‘mobile device apps’ only remains a mystery, but it works. Most of the time.
Up is simple to use. Grab a photo in the Mac’s Finder, drag and drop it to Up, click to upload to Instagram. Options are nominal but most of the ones you want.
For example, Up lets you add captions to each photo (you’re not stuck with the shameless self promotion caption). Plus, you can upload H.264 movies, either square or not square.
Even high quality photos taken by a DSLR and saved as Photoshop files can be uploaded to Instagram.
Is this legit?
Yes, Up works fine and makes it easy to upload photos to your Instagram account with little more than drag and drop, enter a caption, and click to upload– when it works. As to the legalities, I don’t know. Facebook likes to exercise micro-control over the upload process, so, barring some sort of API which allows uploading, I suspect that Up merely emulates the Instagram app on the iPhone and Instagram can’t tell the difference between your Mac and an iPhone.
Some Up users have reported their uploads were blocked from the Mac, while others haven’t had a problem, so, as always, your mileage may vary.