Looking for gallery add-on
It uses filesets so you just batch upload all your images to the file manager, you add them all at once to a file set and you select the file set when adding the gallery to the page.
As for the longer text, you can add a file attribute to your images and make it a WYSIWYG text editor. Then you make the gallery use that attribute for your text. That's the part where you need a little bit of code. Probably about 5 lines of code.