This page is documentation to the various fundamental size limits in the Pillow implementation.

Internal Limits

  • Image sizes cannot be negative. These are checked both in Storage.c and
  • Image sizes may be 0. (Although not in 3.4)
  • Maximum pixel dimensions are limited to INT32, or 2^31 by the sizes in the image header.
  • Individual allocations are limited to 2GB in Storage.c
  • The 2GB allocation puts an upper limit to the xsize of the image of either 2^31 for ‘L’ or 2^29 for ‘RGB’
  • Individual memory mapped segments are limited to 2GB in map.c based on the overflow checks. This requires that any memory mapped image is smaller than 2GB, as calculated by y*stride (so 2Gpx for ‘L’ images, and .5Gpx for ‘RGB’
  • Any call to internal python size functions for buffers or strings are currently returned as int32, not py_ssize_t. This limits the maximum buffer to 2GB for operations like frombytes and frombuffer.
  • This also limits the size of buffers converted using a decoder. (decode.c:127)

Format Size Limits