Fix missing images in GraphicsMagick tool help and update ToolShed dev repo link #2694

Job	Run time
Setup cache and determine changed repositories (3.11)	1m 14s
Lint tool-list (3.11)	53s
Lint Python scripts (3.11)	21s
Lint R scripts (ubuntu-24.04, release)	2m 18s
Check file sizes	20s
Test tools (2, 3.11)	3m 2s
Test tools (1, 3.11)	3m 33s
Test tools (0, 3.11)	3m 16s
Combine chunked test results (3.11)	38s
Check workflow success	3s
Deploy	0s
Report deploy status	0s
	15m 38s

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