I was going to ask "What's the optimum size for images created on Photoshop for use in videos?" but it looks like my question is answered @ https://forums.adobe.com/thread/1384976 and https://forums.adobe.com/thread/450798
However, that sounds like a pretty complex/tedious process - a lot of what he talks about is actually a little over my head - and I wondered if it's possible to cut corners without sacrificing too much quality.
For example, imagine a video that features pretty basic png's and jpg's, including some simple black-and-white drawings and some images with multiple colors but not works of art. If I just use 600 pixels wide as a default for creating my images before importing them into Premier Pro, will they probably look OK?
If an image doesn't look so hot, I could just delete it from Premier, then recreate it in Photoshop with a bigger width and reimport it into Premier, right?
I would NOT make images smaller than my video frame-size. So if you're making a normal high-def 1920x1080 video, I would make them either that pixel size or a doubling of it. If you double them, you can zoom and scale in without pixelating.
If you take a 600 pixel long-side png and put it on a 1080 timeline, ain't gonna look so good ...