here in the picture you can see the unclear pictures make it difficult to get the exact sketches.
You need to increase the scan/photo resolution but be aware of the maximum limit of 4096 x 4096.
From 2019 SOLIDWORKS Help - Sketch Picture
If you insert a sketch picture of a .tiff file, the resolution is limited to 4096 x 4096. Files that exceed this limit are cut in half until both dimensions meet the limit. For example, if you insert a .tiff file that is 5000 x 3000, the file is reduced to 2500 x 1500.
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