The included folders: "20 Frozen Photo Overlays" @ 2000 x 3000 pixels, "50 Aurora Photo Overlays" @ 2000 x 3000 pixels, & "50 Colorful Photo Overlays - Vol. 1" @ 4096 x 2160 pixels, include both jpg images and .png with transparency. The remaining .jpg-only folders are: "30 Stars Photo Overlays" @ 2000 x 3000 pixels, "50 Cinematic Light Leaks Photo Overlays - Vol. 1" @ 4096 x 2160 pixels, "50 Colorful Light Leaks Photo Overlays - Vol. 1" @ 4096 x 2160 pixels, and "50 Dreamy Photo Overlays - Vol. 1" @ 4096 x 2160 pixels. The 3 other included files are a ReadMe.txt with basic Photoshop instructions, Overlay Action.atn, which is a sort of instruction/demo as a Photoshop action, & .DS_Store for MACs.
Quality is decent, though you'll see some pixilation if you zoom in enough. Checking image properties in File Explorer you'll see the .jpg images showing 72, 96, or 300 d.p.i., which is sort of irrelevant until or unless you're printing -- the dimension in pixels is what you've got, and you set the d.p.i. in your editing app prior to printing... the print size will be smaller at 300 d.p.i. than at the Windows screen resolution of 96 d.p.i., but the quality will be much better. Though the instructions talk about Photoshop, you can use these overlays in most all image editing software, though sometimes it may take a bit of ingenuity, e.g., selecting the overlay colors, then copy / pasting to eliminate the overlay's background.
How/why to use one of these overlays?... when you look at many of these images it's hard to imagine why someone would want to stick a swirling mass of color in the middle of a photo of say your better half. And that's very true -- why would you do that? Well, other than blocking out the face of an ex, you generally wouldn't apply them as-is, but rather you'd set them to be mostly transparent, and/or to effect the colors in your photo underneath the overlay. It's just a way to spice things up a bit if you're into that sort of thing, and actually can work out to be pretty subtle.