Orignal issue is
Having an extra border on the right and bottom side of images

Root cause comes from
https://libvips.github.io/libvips/API/current/libvips-resample.html#vips-resize

When upsizing (scale > 1), the operation uses vips_affine() with a VipsInterpolate selected depending on kernel . It will use VipsInterpolateBicubic for VIPS_KERNEL_CUBIC and above. It adds a 0.5 pixel displacement to the input pixels to get center convention scaling.

The fix
Enable vipsAffine to use Extend option value and send it to lipvips
This will change the default from the one that libvips use which is background to the ones that bimg use which is C.VIPS_EXTEND_BLACK
But because the lip add extra 1 or .5 pixel the background is considered black anyway so this will not affect anyone but will fix the bug of having a border on the right and bottom of some images

Creating 100x100 white jpg reproduced the issue if it is scaled even to 101x101 with these options

bimg.Options{
		Width:         width,
		Height:        height,
		Embed:         false,
		NoProfile:     true,
		StripMetadata: true,
		Quality:       100,
	}

now adding this make it works

		Extend:        bimg.ExtendCopy

100x100

500x500

Note the more you scale the image up the darker and thicker the boarder gets