Step 1

Select the instagram photo you wish to use

Step 2

Using your mouse, right click on the image and select "View Page Source"

Step 3

On line 46 you see this:

The image URL you are looking for is found here. It always begins with "https" and it ends with "jpg". Easy to find.

Step 4

Copy the image URL and go into your Steemit settings to paste it there.

And that's it! You now have a new profile pic!