Please share your site url.
So that i can check and provide you exact solution here.
Can you please share password
Hey @PP_World, seems like you removed the password, so I'll assume that Q2 is obsolete.
On Q1: I've had the same problem myself. Fo fix this, I'd recommend you uploading two different images: One for desktop with a very wide aspect ratio (something like 2:1) and one optimised for mobile (can be 1:1 or even 9:16). If you use only 1 image for both platforms, one of them will look weird.
For my store, I loaded the same image into Figma and then cropped it to two different versions which I then uploaded. You can also use this technique if you add more photos to the slideshow to ensure that they are always identical in size and the page doesn't jump when you click through the slide show.
For a demo, check out my store here: https://www.tylkozdroweprodukty.pl/