How to determine whether an image is streamable?

[abukaj]

I am developing a server for automated processing of BIG images (size of 22500x17500 is not the greatest possible)
To process them in a finite memory I need to convert them first into an RGB stream.
Stream (described as "a lightweight tool") seemed to be a perfect tool to do so, however after some benchmarking I discovered that there are formats (like JPEG2000 or even grayscale PNG without interlace) for which stream is not "lightweight" - instead it hogs a vast amount of memory:

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$ /usr/bin/time -f '%M' stream -identify R602_s154_BDA_NR_10x_plainGS.png /dev/null
R602_s154_BDA_NR_10x_plainGS.png PNG 22500x17500 22500x17500+0+0 8-bit PseudoClass 256c 50.15MB 22.800u 0:17.699
12319344

How can I determine, whether an image can be streamed in a reasonable amount of memory, and with no temporary file use?
I can of course use:

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$ ulimit -v 512000 -n 5

and check if stream crashes, but I look for a more elegant solution.