A Dynamic Bitmap in TouchGFX is not necessarily just loading a BMP, dynamically. It means that you can modify a piece of memory at runtime and treat it as a Bitmap in TouchGFX. But, now that we're on the subject, you're right that the dynamic_bitmap_example from TouchGFX 4.8.0 has not made its way into the designer yet.
A Dynamic Bitmap in TouchGFX is not necessarily just loading a BMP, dynamically. It means that you can modify a piece of memory at runtime and treat it as a Bitmap in TouchGFX. But, now that we're on the subject, you're right that the dynamic_bitmap_example from TouchGFX 4.8.0 has not made its way into the designer yet.