Just want to add... and nobody's complained to me... that I think it best to ask before manipulating another's work and re-posting. Some might take great offense at that, and I would rather be proactive than find myself in the middle of an argument over it.
Craig raised this pertinent point and it something i had not thought about a great deal but i guess it needs to raised. I also post on TrekEarth and i'm so used to having my images edited and editing other peoples images in a Workshop sub forum . Often it's little tweaks and minor editing, lots of cropping and resizing etc and i learned a great deal about Photoshop and what it's capable of doing. Sometimes the images were altered to a great extend as there was artistic merit in them ie for example a high contrast image with loads of texture was converted via PS into a Charcoal type to demonstrate what could be done.
And Jim Evans nailed the point; as long as it's done to improve and not degrade the image (Digital Graffiti, Defacing etc) and all credit for the image is given to the original author .
Personally if someone took my Image and altered it in a malicious way - yes i would be upset. On the other hand if it was altered, the workflow/editing explained and it was done to improve the image or demonstrate something within a PS type program - i would have no Problems with that at all; that would be within the Forums Mission Statement of 'Learn all you can - Share all you can'
In light of this and other tweaks that others and i have done of late, may i suggest to Craig a SubForum specifically for the purpose of demonstrating edits or showing before/after shots etc. as often i (and i'm sure others)see something from a different point of view and kindly point it out etc.
If not - i will ask the owner's permission first before editing any future stuff
as i don't want to offend anyone here by suggesting they took a 'bad' photo but on the contrary offer a constructive critique and learn what others do in digital post processing