After a long time working on this upgrade, I've reached the point where I think that it's better to release it and write all the documentation that I had in mind afterwards, so expect more updates about all the features in the following days.
Since quite a long time ago I felt that the name "ImagePaste" wasn't correct for a plugin that allows to also drop files and since version 3.0 offered two buttons to upload files or images with just two clicks and get them inserted into CKEditor.
So with along a new feature set, the main change (meaning the change that will cause more problems for existing users because instead of just replacing the files now you have to edit again your config file) is the rename of the old "imagepaste" to "simpleuploads"
That name tries to explain better what it does, it's not only about "images" and not only about "paste", it's a set of features to offer the users a way to "upload" files in a "simple" way.
The best way to check how it works is to test the demo.
Skipping the explanation about the existing features, the new ones are focused on the dialogs of CKEditor and improving the upload progress:
When you upload a file in the editor, now you get a progress indicator and the option to cancel the upload. The existing progress for images has been improved to also include the cancel option.
The plugin now integrates into the CKEditor dialogs, if it finds a "quickUpload" button it will be replaced with its own one to offer the same simple upload (click button, select a file and you're done instead of having to press the "upload to server"), as well as progress information, cancelation option and the full control on the upload (modify the upload URL, check file size, extension, automatica validation with a whitelist or blacklist...)
And besides modifying the QuickUpload button, the dialog itself now becomes a drop target, you can drop a file from your computer on those dialogs (even if there's only a browse server button is enough) and it will be uploaded and the url of the dialog filled with the new URL.
Another improvement in this version is the inclusion of optional parameters in the upload data, for example if you want to use some anti-CSRF token, modifying the QuickUpload system in CKEditor required some tricks, but now it's a piece of cake. Ditto if you want to add for example a checkbox to scale the image to a maximum, just before the upload begins there's an event where you can control many features.
I'll try to provide examples about how to customize CKEditor with this plugin so you can easily upload files and do whatever you want with them, so keep an eye on the blog because I'll try to write new posts explaining different ways to use the plugin. I've created now a main page here to provide a central point for all the information about SimpleUploads.
PS: currently I really dislike the comment system in Blogger because I don't get any notification when someone comments a post, so I might move to another platform if this bug persists. Meanwhile, have a little patience if I don't reply, it's usually better to send me a mail or direct message by + me.