ImageMagick is notoriously questionable. It was originally written, I believe, as a local command-line tool for users to work with their own images, so security and untrusted input were not primary concerns.
Additionally, image manipulation is inherently challenging - not even due to the actual manipulation of image pixel data, but due to the proliferation of complex image container formats which require binary data manipulation and byte copying in performance-critical code. This is a minefield for secure programming practices because it puts at direct odds performance and sanity checking, as well as encouraging pointer and memory arithmetic and unsafe access.
seems to me that there is no limit to available room. well, i suppose we're capped by the collective capacity of local storage and storage service providers.
ImageMagick is a particularly poor choice because it will try parsing a thousand formats your users will never upload. That's a lot of code to leave exposed to the internet.
