Fixes bug in `overlay_images` occurring for 16bit images #243

Job	Run time
Setup cache and determine changed repositories (3.7)	4m 43s
Lint tool-list (3.7)	31s
Check file sizes	6s
Lint Python scripts (3.7)	8s
Lint R scripts (ubuntu-20.04, release)	1m 23s
Test tools (0, 3.7)	4m 33s
Combine chunked test results (3.7)	33s
Check workflow success	1s
Deploy	0s
Report deploy status	0s
	11m 58s

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