Read write permissions could affect the step's ability to open the file, but I think that would also keep the thumbnail from displaying the image--which is why I didn't have any suggestions for you the first time you posted this question.
Re-examining your file path suggests the issue.
With your Open URL step, replace the backslashes (\) with forward slashes (/).
The back slash is the "escape" character in FileMaker text expressions that tells FileMaker to take the following character as a literal character and not as an operator with special meaning when it evaluates the expression.
\" for example, allows you to get a " into a text expression instead of FileMaker interpreting it as the end of a literal text string.
Thanks, I'll try that.
I posted the question again because I'd tried creating a simplified database with just the image data - no relationships - and got the same result.
Thanks for taking a second look!
Sadly, even when I re-worked the fields to have a / instead of \, the files won't open. Ah, well.
Thanks for your help!
On my colleague's computer, the script opens the file just fine.
You need to figure out what's different between the two computers. If he could see the thumbnails and you couldn't, I'd suggest checking to see if the two of you are mapping the same drive letter for this shared folder.
When I look at your example file path, there seems to be something missing. Shouldn't there be either a volumne name ( mac ) or a drive letter (Windows) at the beginning of that path?
We bypassed the need to ensure that everyone's using the same drive letter by using the server names as the network sees them. In the url file:\\server\folder1\FM-Data\FM-Files\Objects\264_01.jpg, "server" is the same drive that shows up as a network place on all our machines. We use the same syntax for opening pdfs and doc files, without issue. (To be honest, I'm not entirely sure why it works).
I will investigate what everyone's default settings are as far as image management software go - I'm using Windows Picture Viewer, but I believe she's using Picasa.