When i add a new item on the backend and save the item without selecting an image, its fine. But if i select the image on the first go, i get

403
Forbidden
Access to this resource on the server is denied!

using 2.5.22 and 2.6.8

Are your file/folder permissions correct?
It should be 755 for folders and 644 for files.

Admin Tools can fix any read/write "file" permissions on your site, to what they should be. But, if your server's "owner" permissions for files are not properly setup, in other words, if Joomla cannot perform read/write operations via PHP, then it will not work properly. Either enable the Joomla! FTP layer or better still, contact your hosting company and ask them to fix any "owner" related permission issue

Finally is this a new issue, did it work in the past and it stopped working all of a sudden?

i have used admin tools to set the permissions but,

if the permissions was wrong, surely it will not work when i select an image on a already saved item - which it does. As i said, if i add new item, give it a name and some text and save it, it works - if i then go to the image tab and select an image from my pc and save - it works.

its just forbidden when i do it all in once.

it is definitely a new thing - from when i can not say as i had users complain for some time but never had time to really look into this.

my hosting provider had a go at it and found it was a rule on their firewall that caused the problem - he white listed it and it works now

thanks you may close

Nice to hear that the issue is solved.