AfterEffects Output Video File Resizing?

Please just drag your screenshots to the reply field on this forum or use print screen and paste. I makes it a lot easier for us to help you.

You have chosen to customize your output module settings and have picked a camera format that is 1440 X 1080. Unless you are an expert in video standards, formats and compression you should not be messing with comp settings. If you see custom in a comp or render setting they you have probably done something wrong.

If you are supplying the render to someone else have them specify the format, color and compression settings. If it's for your own use then choose Lossless, or lossless with alpha from the Output Module presets. This will give you a production master of the comp. If you are rendering for delivery either drag your production master to the Adobe Media Encoder or open up your AE comp in the AME and use one of the H.264 presets that matches your comp frame size. The YouTube presets will give you a file that anyone can view.