I have a page in inDesign document that i want to be fully covered by an image. I have added bleed (3mm, the page is A5 size) due to printing but if i just extend the image to the bleeding area some of the image details in the edges will be cropped. How can i avoid that? The image should cover the whole page but contains info around the edges that should be printed.
An image would need to extend over the edge of the sheet to form a bleed. So you'd need to extend the image itself if there are parts of it that you don't want to be cut off.
It's possible using content aware filling in software such as Photoshop or even free software such as GIMP. Success for this kind of automatic filling is often dependent on the kind of image. It may not work for everything. Manual cloning may be required.
Anyway, to do it, you'd need to expand the canvas, select the image, invert the selection, then in Photoshop do Edit > Fill, and choose Content Aware. In GIMP this could be achieved using the Resynthesizer plugin (Filters > Enhance > Heal Selection). This will essentially fill the extra space around the image, extending it.
Example in Photoshop
and in GIMP