smaller images from linking Word doc not showing in RH8 Webhelp

I am using RH8 and linking Word Documents.  Will generate as WebHelp.  All images are pasted into the word documents using Snagit.  The images are varying in size and need to be that way.  It seems as though RH8 imports larger images as .jpg files and display fine but converts the smaller ones to .png files and they are not displayed.  Only a box is displayed saying the image file is missing for the smaller .png files. The larger .jpg files display fine.  Why are they coming in as different types?    Does anyone know of a work around to fix this?  Upon searching the forum for an answer I only found a script that will make all images one size.  Is there a setting either in Word or RH8 that needs to be adjusted?  Thank you for your help.