415kB x 8 Images isn't a massive amount of Memory (3.24MB)
So I'd assume you have a few more images being loaded.
Now as to how to approach Loading these Images... well because of AGK's Memory Management (or lack thereof)., while you do want to load them during a Loading Screen; you want to ONLY load specifically what will be used in a given Level.
Also AppGameKit doesn't use Image Compression., just doesn't support it (or well it does but it's disabled, like a lot of other clearly planned but never implemented features; like Cube Maps, Volume Maps, Custom MipMaps, etc.)
So your images will take up a RAW Space... this is a simple look-up table of common image sizes.
2048x2048 (16.4 MB)
1024x1024 (4.1 MB)
512x512 (1.0 MB)
256x256 (256 kB)
128x128 (64 kB)
Notice how doubling the resolution, quadruples the memory space... now what I find strange about AppGameKit is given the focus on Mobile Development and specifically supporting "Less Capable" (i.e. Low-End / Legacy) Handsets; that more effort wasn't put into supporting 8bit (256 Colours) and 16bit (65535 Colours) RGBA Values., as these do dramatically reduce the memory footprint by a Factor of 4 and 2 (respectively).
512x512 32bit (1.0MB)
512x512 16bit (512kB)
512x512 8bit (256kB)
But then the same is true with Hardware Colour Compression., such-as Binary Compression (aka BCn).
As you can get 32bit Colour Depth; at (up to) 25% the Memory Footprint...
512x512 32bit RAW (1.0MB)
512x512 32bit BC7 (256kB)
And while the trade off used to be noticeable colour shifting, banding and artefacts... today most Texture Compression Tools., provide a near 1:1 with the original; meaning you're just getting a smaller memory footprint.
As noted., it's strange that this wasn't considered a priority to support; and still isn't supported.
Where-as if you were to use Dark BASIC Professional with DDS Images., well this is 100% supported... just a shame DBP doesn't support Mobiles (Android / iOS / Windows Mobile)
So yeah, all you can really do is use smaller resolution images.
The other thing you can do is ensure that Auto-Generated MipMapping is disabled., as keep in mind this creates up to 7 Levels of Smaller Images; which is useful to reduce Memory and Processing Overhead for "Distance" Textures in 3D Games... as it would swap out a smaller image at a greater distance.
But while each level is Divided by 2 of the Previous Level
(i.e. 1024 > 512 > 256 > 128 > 64 > 32 > 16 > 8) each of those levels also uses extra memory space., so unless you NEED it... it's best to ensure it's disabled.
As instead of using 4.1MB (for the example above) you'd end up using ~5.5MB instead.
So can lead to some "Hidden" Extra memory Cost for your Images.