Adding resources, player-side?

I’m looking to add resources to a game from the player’s perspective. Is that possible? I know that with the “Load Images from a URL” extension, I can create a modifiable system for the game. However, it seems to replace the game’s existing resources with the new ones, and I can’t seem to find a workaround.

Is there a way to incorporate resources without pre-loading them through the engine before the game is compiled into an executable? Or is there a possible workaround?

I haven’t been able to create any examples yet as the design may change significantly depending on how I’m able to execute it. The game incorporates elements like visual novel-style events and team-based automatic battles. I want players to have the ability to customize their own characters and events. One idea that I’ve come up with is to create placeholder units, such as “ModChara1,” “ModChara2,” and so forth, and then dynamically populate them with their sprites in real-time depending on their context and mods loaded, using the “Load images from URL” extension.

However, for the visual novel part, I’d need at least four different objects for this task, and for the team-based auto-battler, the number could be much higher depending on the size of the player and enemy armies, potentially reaching into the fifties. So, if someone could shed a light on an workaround, it would be amazing.