Functions to conver a DynamicImage (JuicyPixel) to a BMP (bmp) to us in Gloss

load-png.hs

import qualified Data.ByteString.Lazy as BLazy

import Data.Bifunctor
import Graphics.Gloss
import Graphics.Gloss.Data.Picture
import Codec.Picture
import Codec.BMP

parseBMP :: BLazy.ByteString -> Either String BMP
parseBMP b = first show (parseBMP b)

loadPng :: FilePath -> IO Picture
loadPng fileName = do
    result <- readImage fileName
    case result >>= encodeDynamicBitmap >>= parseBMP of
        Left error -> do
            putStrLn error
            pure blank
        Right bmp -> 
            pure (bitmapOfBMP bmp)