The imageShadowColor configuration option in your gallery's XML file is currently set to:
imageShadowColor="rgba(0,0,0,1
0
0)"
The 4th parameter of the rgba(r,g,b,a) value should be set to 0 for the color to be fully transparent so change it to the following:
imageShadowColor="rgba(0,0,0,0)"
For others reading this thread, you can remove the drop shadow on the main images by either setting imageShadowBlur="0" (in JuiceboxBuilder-Pro's 'Customize -> Main Image' section) or by setting the opacity of the imageShadowColor to zero, e.g. imageShadowColor="rgba(0,0,0,0)" ('Customize -> Color').
The 4th parameter of the rgba(r,g,b,a) value is the opacity (the alpha channel).