When you go to save in photoshop there are a lot of different variants. The best way to think about it is “I know less than 50% of these”.
saving a file in Photoshop
the norm but does lower the more times it’s saved. It is a very versatile format but a lossy file type.
It is effectively a PDF, but made from Photoshop. Contrary to popular belief, photoshop does support vector text. Assuming you’ve left your text as editable text anyway. Photoshop PDF’s support layers too, but end up as huge files.
The golden child of files types. They maintain quality, huge amounts of, file-size is workable. They hold layer information, spot colour information and more or less any information you save. They even interact with other software fantastically in cool ways which we’ll eventually learn.
Export for web and devices
This is the other way of saving from Photoshop. Using File > Export > Save for Web (Legacy). We can save files that are optimised for web. From here we can choose JPEGs, PNG’s and GIF’s. These files will be optimised to be much smaller files size for web use. GIF’s will even give you the option of saving with animated options. When you are saving an image for web as the size it will be presented at otherwise it will slow the website down trying to load a large image.