Our BT81x series (BT815, BT816, BT817, BT818) have a Quad-SPI NOR Flash interface. You can store your images on the NOR Flash chip and EVE can then access them directly.
The BT81x can also use the ASTC format which reduces the image size whilst retaining good image quality. The EVE-attached Flash can also store assets such as fonts, video and animations, ensuring that these can all be used even where the host MCU has a small Flash size.