Why are my files saving so small?

[Howard36291175rvoj]

Forgive me, I am relatively new to Photoshop. I don't know why my files are shrinking in Photoshop. I open a 3.5mb photo from my camera into Photoshop and edit it. I then save it as a PSD file and then export it as a PNG file, only to find the file is now 853kb and even less if I try to export it as a JPEG, even choosing the maximum file size (12). Is there something in my settings that is compressing my file? I am looking to sell my photos and they need to be a certain minimum size to do so. Thank you in advance for your help!

[D Fosse]

Compression is exactly what it is.

The jpeg compression algorithm is particularly aggressive, as well as destructive, non-reversible and cumulative. The reason it's still widely used is that it's incredibly effective, and will shrink a file to 2-5% of native size, even at the highest setting. A jpeg is always compressed, there is no such thing as "maximum quality".

PNG compression is non-destructive, but not quite as effective as jpeg. It will still reduce file sizes considerably compared to uncompressed files.

PSD and TIFF can be uncompressed or compressed. PSD compression is set in Preferences, TIFF compression in the save options dialog.