You can. Just get it from the Minecraft Forum. Run it, then you can make and edit skin files for Minecraft.
download the reference skin after logging in and clicking 'profile' then edit with your preferred image editor keeping the same dimensions
No
By going on to the minecraft website and clicking on profile then press upload image and upload your image from there
You can technically edit any image but the app Instagram does not have an image editor...it just applies filters.
Link below this answer.
yes
Inv Edit basically allows you to spawn in items from your inventory.
if you want items in minecraft the best edit i know is INVedit. download it, open world iventory and edit it. save it to your world next
I have posted a link in the related links for the image of the ID list for Minecraft. You can zoom in the image, as it is a little small, by clicking on the image where you wish to zoom in at.
Someone with photoshop skills can edit your scanned image very easily in photoshop.
No, it does not cost anything.