The Instagram phone app features a quick way to view all of your notifications on your phone by tapping the speech bubble in the main menu. This screen lists all of the instances in which other users mentioned you in a comment or liked your posts. The Web-based version of Instagram doesn't have a notifications screen as of January 2014, but you can still view the notifications of individual Instagram photos on your PC.
Log in to your Instagram account and click your profile name in the main menu.
Select "View Profile" from the drop-down menu that displays.
Hover your cursor over the photo for which you want to view notifications. The site displays the number of comments, as well as the number of likes, that the photo has received.
Click the photo to read the comments for the photo and to see the users who liked the photo. The site displays the usernames of the last three users who liked the photo, as well as the number of users.