Summarize this article in one sentence.
MS Paint has an icon that resembles a painters pallet.  Use the following steps to open MS Paint for Windows.  Click the Windows Start menu in the lower-left corner. Type "Paint". Click the MS Paint icon. Use the following steps to open an image in MS Paint.  Click File in the upper-left corner. Click Open. Select an image. Click Open. You don't want to edit the size of the original image.  Save the image as a separate copy.  Add "thumbnail" or something similar to the end of the copy of the image (i.e. weddingphoto_thumbnail.jpg).  Use the following steps to create a copy of the image:  Click File  Click Save As. Type a name for the image next to "Filename". Click Save. It's in the upper-left corner above the box labeled "Image". It's at the top of the "Resize and Skew" window. 10% is a good size for a thumbnail image.  Larger photos will need to be reduced greater. Alternatively, you can select "Pixels" and type the exact dimensions in Pixels you want the image to be next to "Vertical" and "Horizontal". This reduces the size of the photo. Use the following steps to reduce the size of the photo.  Click File  Click Save.

Summary:
Open MS Paint. Open an image you want to make a thumbnail for. Create a copy of the image. Click Resize. Tick "Percentage". Type the percentage you want to reduce the image size next to "Horizontal" or "Vertical". Click Ok. Save the photo.