Slideshow photos don’t appear long enough

Do you understand this? How would you phrase correctly?

Is it natural to say : “appear long enough” and “change too fast”?

Do you understand “pictures are at 45%” meaning they are upside down but to the side.

please help phrase

The photos don’t appear long enough in the slideshow. They change too fast and some pictures are at 45%. You need to pivot them so they are all straight.

thank you