>>which -all padarray_algo
C:\Program Files\MATLAB\R2016a\toolbox\images\images\private\padarray_algo.m % Private to images
C:\Program Files\MATLAB\R2016a\toolbox\images\images\@gpuArray\private\padarray_algo.m % Private to @gpuArray
>>
If it's not, try
rehash toolboxcache
If that doesn't work, then
restoredefaultpath
rehash toolboxcache
