420a421
>     no_frame_optimization = im.encoderinfo.get("no_frame_optimization", im.info.get("no_frame_optimization"))
443,447c444,445
<                 previous = im_frames[-1]
<                 if _get_palette_bytes(im_frame) == \
<                    _get_palette_bytes(previous['im']):
<                     delta = ImageChops.subtract_modulo(im_frame,
<                                                        previous['im'])
---
>                 if no_frame_optimization:
>                     bbox = im_frame.getbbox()
449,457c447,461
<                     delta = ImageChops.subtract_modulo(
<                         im_frame.convert('RGB'), previous['im'].convert('RGB'))
<                 bbox = delta.getbbox()
<                 if not bbox:
<                     # This frame is identical to the previous frame
<                     if duration:
<                         previous['encoderinfo']['duration'] += \
<                             encoderinfo['duration']
<                     continue
---
>                     previous = im_frames[-1]
>                     if _get_palette_bytes(im_frame) == \
>                     _get_palette_bytes(previous['im']):
>                         delta = ImageChops.subtract_modulo(im_frame,
>                                                         previous['im'])
>                     else:
>                         delta = ImageChops.subtract_modulo(
>                             im_frame.convert('RGB'), previous['im'].convert('RGB'))
>                     bbox = delta.getbbox()
>                     if not bbox:
>                         # This frame is identical to the previous frame
>                         if duration:
>                             previous['encoderinfo']['duration'] += \
>                                 encoderinfo['duration']
>                         continue