2019 Honda Insight Hybrid Owners Manual pg 244.
For EX/LX Wallpaper Setup
• When importing wallpaper files, the image must be in the USB flash drive’s root directory. Images in a folder cannot be imported.
• The file name must be fewer than 64 characters.
• The file format of the image that can be imported is BMP (bmp) or JPEG (jpg).
• The individual file size limit is 2 MB.
• The maximum image size is 1,920 × 936 pixels. If the image size is less than 480 × 234 pixels, the image is displayed in the middle of the screen with the extra area appearing in black.
• Up to 255 files can be selected.
• The wallpaper setup is limited while driving.
Also note pg 245:
When the file size is large, it takes a while to be previewed.
pg 269
For Touring Wallpaper Setup
The wallpaper you set up on Clock Faces cannot be displayed on the driver information interface.
• When importing wallpaper files, the image must be in the USB flash drive’s root directory. Images in a folder cannot be imported.
• The file name must be fewer than 64 characters.
• The file format of the image that can be imported is BMP (bmp) or JPEG (jpg).
• The individual file size limit is less than 2 MB.
• If the USB flash drive does not have any pictures, the No files detected message appears.
• Up to five pictures can be imported.
• The maximum image size is 1,920 × 936 pixels. If the image size is less the image is displayed in the middle of the screen with the extra area appearing in black.