decode some powershell malware from image

x.py

ret = [ 0 for _ in range(40000)]                                                                            

for i in range(26): 
  for j in range(800): 
    try: 
      px = img.getpixel((j,i)) 
    except: 
      continue 
    ret[i * 800 + j ] = math.floor((px[2] & 0xf ) * 4 * 4 )  | (px[1]&0xf) 
                                                                                                                  
with open('x.ps1','w') as f: f.write(''.join(map(chr,filter(None,ret))))