ImgurUpload is a tool that allows users to drag images into their comment box. They will be uploaded via AJAX using the Imgur v3 API. You need to register for API access - see the plugin's settings page for the link to do this.
The front-end of the plugin has code to detect touch-enabled devices and add a fallback "Add Images" button.
Caveat emptor: I have only set this up and tested it on my own forum, but I will be *very receptive* to any feedback provided from users of other forums.
You may also contribute pull requests directly, if you so wish. The repository is at https://github.com/jamesinc/imgur-upload
1.1.10 (August 28, 2017)
- Made thumbnail size configurable
- Removed client-side image resizing. Needs further development to support EXIF metadata (particularly orientation) + resolve bugs on macOS/iOS devices.
1.1.9 (August 23, 2017)
- Fixed a bug when multiple edit comment forms are open at once
1.0.13 (October 29, 2016)
- Added a setting in the plugin settings page that allows drag'n'drop functionality to be disabled. It is enabled by default.
1.0.12 (September 8, 2016)
- Added a setting in the plugin settings page that allows the 'Add Images' button to be enabled for desktop users. This makes life easier for users who are not aware of drag'n'drop.
1.0.11 (September 3, 2016)
- Added resize images option to plugin settings page. When enabled, this will limit the resolution of displayed images to "huge thumbnail" 1024x1024 size (using path suffixes provided by Imgur), reducing time and data wasted loading large images. The images link to their full-size originals.
1.0.10 (September 3, 2016)
- Changed Imgur image URL scheme from HTTP to HTTPS. No idea why the Imgur API doesn't do this by default.
1.0.9 (July 19, 2016)
- Added support for clipboard image data paste operations
1.0.8 (June 14, 2016)
- Input now disabled when uploading an image. A loading wheel overlay also appears
1.0.5 (May 23, 2016)
- Updated packaged version of DropzoneJS* (fixed FF bug)
- Added source maps for compressed JS files
1.0.3 (November 27, 2015)
- Added preventDefault() event capture to "Add Images" fallback anchor, to prevent page from scrolling to the top when it's clicked
NB: (2017-08-27) it has come to my attention that the plugin in its current form is not compliant with Imgur TOS. I will be releasing an update shortly that adds a TOS-compliance option to use Imgur's "embed" code instead. Imgur have been pretty friendly so I don't think there's any need to panic unless your forum receives truly massive traffic.
* NB the packaged version of dropzone.js is modified to remove some default request headers that Imgur rejects.