Firstly, DOWNLOAD MINECRAFT OR PAINT.NET
if you already have those, skip to the tutorial

HOW TO MAKE YOUR GLASSES TRANSPARENT
1. Make a skin with glasses. if you already have that type of skin, let's move on 2 NUMBER 2 (no pun intended)
2. Save it or load it on paint.net.
3. Create a new layer and cut out the glass part of the glasses and paste it into the new layer
4. Change the opacity to whatever you want in Layers > Layer Properties > Opacity
5. Click save and change it from PDN to PNG with the bar below the file name
6. LOAD IT IN!!! (take note, that these transparencies don't appear in skin editors so do this after you are really done (ofc unless you wanna do it again)

THANK YOU!
The Photoshop version is in the vid