How can I optimize image quality and adjust text opacity in Shopify?

hi

here are some questions I have, would love osmeone to help:

§ many sites have the ability to automatically create several sizes from each uploaded image, and know which image to use for quality and speed.
can shopify do that?right now images look very bad :disappointed_face:

§ I think there is an opacity property assigned to the body text.
I would like to reset it to no opacity. do you know where I can find the code for that?

§ I’m beginning to understand that maybe I can create different layouts through the edit code section.
any ideas on how to go about it?

§ what is the meaning of “collapse on large screens” in the theme editor?

§ is there a way of changing the look of the paypal button, or replacing it with a standard buy it now button?
I kind of find it off-putting with all these colors there. it’s not that bad, just curious to know, that’s all.

§ is there a way of changing the design of the about page, so I can have the image and text next to each other on large screens?
right now it’s one under the other by default.

Thank You!