WARN: Unable to create a diff image

[maelvls]

I suspect this project is in "sleep" mode, but I'll report this bug since I found a workaround. With wraith 4.2.4, I encountered errors like

WARN: Failures detected:
WARN:    Unable to create a diff image for home
WARN:    Unable to create a diff image for /docs
WARN:    Unable to create a diff image for /docs/concepts/certificaterequest
WARN:    Unable to create a diff image for /docs/concepts/certificate
WARN:    Unable to create a diff image for /docs/concepts/acme-orders-challenges

No error was reported during the "Saved diff" stage. I realized that the "diff" command was called with no fuzz argument (notice the two blanks):

compare -fuzz  -metric AE -highlight-color blue shots/home/1600_chrome_current.png shots/home/1600_chrome_next.png shots/home/1600_chrome_diff.png
#            ^^

I fixed this by adding the fuzz parameter to my config.yaml.