In example 1a we bring PicMapTool over an image which in this case is a charting program called MegaStar used for astronomy.  Since the PicMapTool screen shows the screen below we see our chart program.   The first thing we do is draw a line with the mouse on the bottom between +34 21  and  +34 30.  We then right click and select 'Set scale from last line'.  We type in 9 so e will then be calibrated for 'minutes' which is the 21 to 30 units.   Now we draw a line on the screen area from the bright core of the large lower galaxy to the top galaxy core and we then see in the 'Lines'  measurement box near bottom left that this was 8 minutes.   You can do this with any picture such as a map of a park or streets.

In example 2 we want to use NexSat weather map to see what the clouds look like at the site we want to go out to use a telescope or camp or hike.   First we lay the tool over a black and white image such as this one I am supplying for California and we then use 'Grab'.  We then visit the  NexSat California low clouds sat image link and click on it to make it the larger picture.  Now move  PicMapTool over the weather map after bringing 'Image Transparency' to the right to make our overlay partially transparent.   In this example the map I have offered for use is the right size for the expanded version supplied by the sat images so no adjustment is needed.  BUT you could also use 'Image Scale' and 'Image Rotation' to scale and align some sort of overlay to whatever scale the screen graphic below is using.

The pattern above is used for astrophotography focus of a telescope.  We try to focus a telescope using a special tool called a Bahtinov Mask that when the telescope is focused is completely symetrical where the middle line is between the 'V'  patterns on each side.   In this example we can right after taking an exposure with the telescope lay PicMapTool screen so that the origin 'O' is in the middle of the pattern then use the Grid Rotation slider to align the grid to the central long line.   Now when focus is perfect it is easy to judge the 'V' pattern to see if it crosses over the  grid lines above and below at the very same relative position to the other side of the V.    OR we can start to draw a line with a click on the central line perhaps 3 grid spaces to the left of the origin and drag the mouse up to the upper leg of the V and note the distance in the 'Lines:' box in yellow here.   Then keep the mouse pressed and move to the lower leg of the V and see if it is the same.  You can without guesswork then know you are in focus or need another focus adjustment.