I've changed the size of the charts in Paint, but only by putting the pointer on the corner until the double arrow appears and then pushing the corner to make the chart smaller. You mentioned that you resized the picture to 25%. How did you do that in Paint. I was looking for something like that but I don't see it under the tabs for Paint. I may have an older version, or just looking in the wrong place.
I do something similar to you. Since I don't have interactive or charting software, I will just do a simple copy of a chart from this site or a delayed chart from the trading platform I use and put it into Power Point since I have that. Then I put the lines, arrows, and text on it. Copy into Paint with a file type of PNG, and I am ready to go. Tried with Trades charts, but I just did not know an easy way to re-size the charts. You have six charts in your post that you have resized. Did you do that in Paint under some tab?