>Your designers want
Sometimes, you need to tell the designers NO. Moving background images don't help people figure out what the weather is going to be.
Honestly if the image is of the current weather it kinda does. I don't mind e.g Apple's weather app design at all
And sometimes your engineers need to be a LOT less stingy. 1GB is clearly overkill for an app such as this, but ~300MB is perfectly acceptable if it works well, looks good and does what it should do.
There is such a thing as overdesign, but when you’re building a modern application, you must trust your designer’s sense of aesthetics and knowledge of UX patterns—two things engineers are often notoriously bad at.