First, you can now select multiple files in the same dialog box box by holding down the Control key while clicking on the files you want to attach.
This saves a few clicks and is definitely a useful improvement.
A much better change is that now you’ll get a progress bar, telling you how much of the files you’ve selected have been uploaded.
Picture Credit: The Official Gmail Blog.
This is definitely an improvement over the old method, where one had no idea if the image had been uploaded, or if the upload had timed out.
I’m now waiting for the next of my suggestions to appear in Gmail … inserting a Google Docs document directly into Gmail and avoid the hassle of uploading anything in the first place!