newt No actually it's not. Try making a blank project and put 20-50 1080p images in the files folder. Notice how previews boots instantly, and there's no increase in image memory use. Now place those same images in a sprite. Boom got yourself several seconds of loading, and that memory use's pretty big. Also done tests on HTML exports, and you can clearly tell the images from files needs to be loaded from the server. They're not loaded in the same way as sprites. Also if you have a text object print the image memory use, you will see it rise considerably once you use the "load from url" action. Restarting the layout makes it disappear, and the memory use is reset.
This is the solution to making projects scaleble. This way you don't have load your entire game just to playtest that one level giving you trouble.
You probably didn't understand what he meant... It actually is pretty much the same. Sprites aren't loaded into memory until they are required in the layout you load into. It is the same as On start layout, all sprites load from url. The benefit is that if those same sprites are used in the next layout after that, they are not unloaded from memory.
Try putting all your large images in a sprite on an unused layout, you will notice if you preview an empty layout, those sprites are not loaded into memory.
You use load from url on any given layout to spread out the loading process, so it doesn't necessarily have to complete all in one tick at the start of layout. This can give your users some heads up so it doesn't look frozen in the event of large amounts of sprites loaded.
There are also advantages such as under the hood sprite sheeting that using the sprite object gives you. Regardless of which method you use, the sprites will need to be loaded in the end and your peak memory use will be the same regardless, so you still have to split up your image memory load across layouts anyway.
Now if there were a specific action to UNLOAD a sprite from memory in a given layout at runtime, that would open up some possibilities in certain fringe cases.