Runtime Image Loader allows to load PNG, JPEG, BMP, TGA, OpenEXR, TIFF and QOI images of into Unreal at runtime without any problems. It creates texture in an asynchronous way so that loading even high-resolution textures will not impact the game and render thread frame times. The same approach is implemented for cubemaps.
Developer's update: The active development of this plugin is completed! It provides an intuitive Blueprint interface that allows to load images without facing issues that exist in vanilla Unreal Engine. That was my main intention and I'm not planning to support more advanced workflows, for example, cache layers, mip generation, rare image formats and OS besides Windows and Android (experimental). However, I always welcome pull requests adding new features.
Support channel (Discord): https://discord.gg/Ujw7QVrWxG
