ImageMagick returns a status of 0 whenever a command or algorithm successfully complete without complaint. A warning code generally is typically just a notice that something unusual occurred but the command or algorithm still completed and most likely the results are still usable. An error means the command or algorithm could not complete as expected and any results are unreliable. A fatal error means the command or algorithm could not complete and the process exits prematurely and no results are returned.

ImageMagick Error and Warning Codes
Domain Description Warning Error Fatal Error
Success the command or algorithm completed successfully without complaint 0 0 0
Resource Limit a program resource is exhausted (e.g. not enough memory) 300 400 700
Type A font is unavailable; a substitution may have occurred 305 405 705
Option a command-line option was malformed 310 410 710
Delegate an ImageMagick delegate failed to complete 315 415 715
Missing Delegate the image type can not be read or written because the appropriate Delegate is missing 320 420 720
Corrupt Image the image file may be corrupt 325 425 725
FileOpen the image file could not be opened for reading or writing 330 430 730
Blob a binary large object could not be allocated, read, or written 335 435 735
Stream there was a problem reading or writing from a stream 340 440 740
Cache pixels could not be read or written to the pixel cache 345 445 745
Coder there was a problem with an image coder 350 450 750
Module there was a problem with an image module 355 455 755
Draw a drawing operation failed 360 460 760
Image the operation could not complete due to an incompatible image 365 465 765
Wand there was a problem specific to the MagickWand API 370 470 770
Random there is a problem generating a true or pseudo-random number 375 475 775
XServer an X resource is unavailable 380 480 780
Monitor there was a problem activating the progress monitor 385 485 785
Registry there was a problem getting or setting the registry 390 490 790
Configure there was a problem getting a configuration file 395 495 795
Policy a policy denies access to a delegate, coder, filter, path, or resource. 399 499 799