fix check for thumbnail object existence

3 jobs for master in 4 minutes and 8 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #76186
mbr
test

00:01:54

passed #76187
mbr
test-chart

00:00:12

 
  Publish
passed #76188
mbr
build-latest-image

00:02:13