I need to put a bunch of photos onto a flashdrive for a TV presentation (not a slideshow, just in folders). What is the best format? Do I leave file size alone and do Image Resize - long edge at 1080 and keep resolution at 300? I get so confused with file size and image size!! Thank you!
I suggest to always leave the file size alone. The resolution also does not matter in this case and you can leave it at its default of 240.
All you need to do is to select a decent JPG quality for your purpose and to have the size in pixel meet your TV, i.e. 1080 vertical. This way the TV does not have to scale and will also be faster to load and display.