Updated this with screenshots to explain after some people having issues resizing.
So this example uses a photo direct from a phone plugged into a computer via usb (this would be the same for a camera plugged into a computer). So either copy and paste the photo you want from the phone/camera to the computer - or resize it direct from the phone computer.
Here I've selected a photo on my phone (opened up photos on phone via computer) and right clicked on the photo which opens a menu. Select "Edit" from the menu.
Resize in Paint 1.jpg
When you select edit - the photo opens up in "Paint" on Windows 10 computer - very large! As it's a full file size photo of about 4 or 5mb usually.
You then click on "Resize" at the top of the Paint menu and another window opens
Resize in Paint 2.jpg
On that window you can see there is either "percentage" (automatically selected) or "Pixels". Select Pixels. There are two boxes with current size in. Change the numbers in the top box to 650 (the numbers in the bottom box will then resize automatically). Then click on Ok. Your photo will be resized.
You then go to "File" (top left of the page) and a drop down menu appears - select "Save As". This is to save your resized photo without altering the original photo size (ie save a resized copy).
Resize in Paint 3.jpg
After moving the mouse over "save as" - move the mouse over to the right and select "jpeg" You want to save it as a jpeg.
Resize in Paint 4.jpg
Resize in Paint 5.jpg
Another Window then opens so you can choose where to save the photo.
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