If they exist you should be able get images from the South Carolina state archives. Company flags were presented as a matter of civic pride, particularly during the first year of hostilities and even earlier, during the late antebellum period. However, company flags had no tactical (or practical) use in the field. For that reason most were sent home for safekeeping.
Sometimes company flags were discovered in trunks by invading Federal soldiers rumaging for valuables and taken as 'battlefield' trophies.
I see that you have posted the question about the 1st Engineer Regiment on the Flags Message Board. Hopefully someone will reply as to whether any flag or flags were carried by this regiment.