Unable to create Gif (even though it's been working fine in many other similar occasions)

[Sheraff]

Warning: imagecreatefromstring(): gd-png: fatal libpng error: Read Error: truncated data in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php on line 113

Warning: imagecreatefromstring(): gd-png error: setjmp returns error condition in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php on line 113

Warning: imagecreatefromstring(): Passed data is not in 'PNG' format in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php on line 113

Warning: imagecreatefromstring(): Couldn't create GD Image Stream out of Data in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php on line 113

Fatal error: Uncaught exception 'Exception' with message 'GifCreator: Under development: 171 Source is not a GIF image.' in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php:132
Stack trace:
#0 /Users/Flo/GitHub/whiteboard-comics/test.php(23): GifCreator\GifCreator->create(Array, Array, 0)
#1 {main}
thrown in /Users/Flo/GitHub/whiteboard-comics/GifCreator.php on line 132

[danielpinon]

The problem is with the post file that is in the temp folder under another name you need to move it to your folder to be able to load it into the generator.