gistfile1.txt

 ✘ moritz@moritz-desktop  ~/mapcrafter  mapcrafter -c world1.7.conf -rf world1.7_day_jpeg -j 8 
Scanning worlds...
(2/4) Rendering map world1.7_day_jpeg ("world1.7_day_jpeg"):
(2.1/2.1) Rendering rotation top-left:
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
8 threads will render 27481 render tiles.
[====================================================================================================================================================================================================] 100.00% 27481/27481 106.52/s            
(2.1/2.1) Rendering rotation top-left took 259 seconds.

Rendering all worlds took 259 seconds.

Finished.....aaand it's gone!
 moritz@moritz-desktop  ~/mapcrafter  mapcrafter -c world1.7.conf -rf world1.7_day -j 8     
Scanning worlds...
(1/4) Rendering map world1.7_day ("world1.7_day"):
(1.1/1.1) Rendering rotation top-left:
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
libpng warning: iCCP: Not recognizing known sRGB profile that has been edited
8 threads will render 27481 render tiles.
[====================================================================================================================================================================================================] 100.00% 27481/27481 66.22/s             
(1.1/1.1) Rendering rotation top-left took 415 seconds.

Rendering all worlds took 415 seconds.

Finished.....aaand it's gone!

Is a world displayed when you open your index.html file?

I just followed the steps below to solve this issue from JampaSax :)

JampaSax commented on 14 Apr 2020
I use GIMP to fix this problem. Open the image that is causing the problem. Then go to Image -> Mode -> Assign Colour Profile, and chose RGB Workspace. And export the "new" image.