Backport (7.9) - Cannot pick a newly uploaded image with the image link picker

I used the 1.09.01 archetype to create a new project. In the cms I upload a new image. In a news document I use the image picker to select the new image. In the dialog the Ok button remains grey, and I cannot select the image.

I tried a png an jpg image, that doesn't make a difference. Even an image that was bootstrapped with the archetype, downloaded and uploaded to the cms cannot be picked.

I noticed this error in the tomcat log, but am not sure if it is related. It seems the upload itself is working fine.

[INFO] [talledLocalContainer] 24.07.2014 15:01:43 ERROR http-bio-8080-exec-12 [DiskFileItem.delete:467] failed to delete
file: C:\workspaces\training\tryout791\myhippoproject\target\tomcat7x\temp\upload_9bfb79ca_0504_44db_9185_e4073bb441cd_
230642214.tmp

I noticed that the uploaded image node has more mixins added on the node, and has much more jcr-properties than the ones that are bootstrapped with the archetype. Can that be the the problem?