There's an Instagram Web Viewer called "Websta" also known as "Webstagram" before. With Websta, you can view posts of the people you follow, like and comment on photos, follow and unfollow other users, see your followers and following, browse popular photos/tags/users, get your RSS feeds, and many other stunning features including: Saving high quality photos and videos. But with Websta, you can't upload a photo or a video to your Instagram account, same as other Instagram web viewers out there.
To save a photo and a video from Instagram:
1. Open your web browser and go to www.websta.me/n/USERNAME of the owner of the photo/video you want to save from.
2. Look for the photo/video you want to save and click it.
3. To save a photo, there's a rectangle button (with 3 dots) in the bottom right of the photo, click it and you can see these options: Thumbnail Size, Medium Size, Large Size, View Original on Instagram. If you want to save the high quality version of the photo, select Large Size and then, right click the photo and save it.
4. To save a video, again, the same procedure as the photo, there's a rectangle button (with 3 dots) in the bottom right of the video, click it and select: Video (m4v) and right click the video and save it.
That's it! Enjoy grabbing photos and videos from Instagram!