image (cropped) scales and plone.outputfilters cache problems

[petschki]

@frisi mentioned in #4 to show possibly involved changes when editing an image with cropped scales. it turns out, that those changes arent visible at all because of portal_transforms caching. the same issue here: https://dev.plone.org/ticket/13536

possible solutions:

• linkintegrity checks and modification events on target documents

[petschki]

related topic ... pretty old though, wondered that this is still around: http://david.wglick.org/2009/image-captions-and-the-portaltransforms-cache/

Two more possible solutions:

• Wait one hour :)
• adjust the cache lifetime like mentioned in the link above

[hvelarde]

@jpgimenez @cleberjsantos this could be related with the problems we are having on the project