Can I reduce App download size by reducing bit depth of images?

UtamicDev 8 years ago updated 8 years ago 3
Our application (iSew) has a number of applications within it. The download times are too long and I have discovered that a number of background images have 24 bit depth. I have reduced this to 8 bit to make them smaller and they still look fine. The size change (only for about 8 background images) was from 17.5Mb to 5.6Mb!

However, will this change the size of the download?

I am concerned that possibly the images are scaled to a standard bit depth which might mean that there will be no change to the download size.
This will reduce the time for the initial download of the App from the App Store however you want to test this on both retina and non-retina devices to ensure the images still look okay on all resolutions.
Also if these images are in In-App purchases, then it will speed up those downloads as well.
Thanks that is a really good answer - straight to the point and highlighting possible issues. We will test it further.