Because the width of the USB connector is standardised, I can easily work it out by counting pixels. I measured the width of some standard USB connectors around my place with calipers and they were all 12.00 +/- 0.02 mm

From your supplied image, 90 pixels = 12.00 mm, thus 7.5 pixels per mm

Also from your pic:

X = 449 px = 60.0 mm
Y = 188 px = 25.1 mm
Z = 299 px = 39.9 mm

I have measured leniently the dimensions, they may be about +/- 0.1 mm, favoring the larger for your convenience so that it fits wherever you plan it to.