Picture blocking

[modeller]

I am working with Vista and I mainly use Windows Live Mail but I also use two other email providers ,Orange and Gmail . I do this to restrict the use to
1. friends and important contacts,
2. less important contacts eg utilities
3. all contacts that I believe may generate junk mail

However I find that WLM block some picture attachments which are considered suspect and dangerous. Which is good in theory but in practice it will often block a simple family group or a view. This particularly happens when it's been sent via an iPhone but if the same picture comes from an iPad or PC there is no problem .
My security setting for WLM is minimum.
I temporarily removed this minimum setting for 10 minutes and my contact was able to send pictures from their iPhone. I then reinstalled it as I thought it was safer.

The strange thing is if the blocked pictures are resent using my other two addresses they are not blocked at all whatever the source.

What does this imply ? Is WLM too diligent or are the others less secure ..