I recently asked a group of heralds what the conventions were on copying heraldic art from OSCAR for re-use in other submissions, and thought it would be useful to write up some notes on the subject here for future reference.
Copying elements from previous submissions to use as clip art when creating new armory is not uncommon. While some heralds are great freehand illustrators, others are not (myself included), and being able to pull charges from an existing image and repurpose them allows those folks to assemble good-looking submissions for the registrants they are assisting.
This practice is widespread and I don’t know of any cases where someone has objected to their art being reused in this way. If you’re one of the many heralds who does this, please don’t take my commentary as a criticism or as pressure to do things differently
However, there is no formal license to do this, and legally each piece of art remains under the copyright of its original creator except where individual or blanket permission is granted for reuse. (Some earlier versions of the armory submission forms included a clause granting permission for use within the society, but the current ones do not.)
(Edited June 20 to add: The “Laurel v2.0” generation of forms, circa 2006, include the message “I understand that with my submission I automatically give permission for the Society for Creative Anachronism to use my artwork and armory for any and all internal heraldic and scribal purposes.” The “Laurel v3.0” forms, circa 2016, omit this language.)
Writing to the original submitter and requesting permission seems like it would solve this problem, but this can be challenging because OSCAR does not expose the registrants’ contact information (sometimes Facebook searches or friend-of-a-friend inquiries will do the trick), and in some cases the registrant may not even know who created the artwork in the first place.
There are several libraries of heraldic images that do grant general permission for use in creating armory for the SCA without special arrangement or attribution, including Bruce Draconarius’s PicDic, Viking Answer Lady’s SVG Images for Heralds, Ailis Linne’s Pennsic Traceable Art book, and my own Book of Traceable Heraldic Art, but none of them is exhaustive enough to contain every possible charge in ever allowable position and style.
Note that all of the above presumes you are creating heraldry or artistic displays for non-commercial use within the society — if you plan to sell products with these images, use them for your business logo, or any other kind of commercial use you really must get in touch with the original creator and negotiate specific permission or you are opening yourself to both civil and criminal liability.
With all that said, finding several different examples of a charge from OSCAR, bringing them all to someone with a good hand, and asking them to draw something in the same vein should be safe as long as they’re using the material for inspiration and not directly tracing or copying them. Direct tracing of period illustrations or no-longer copyrighted armorial texts also shouldn’t create any problems, although you will need to verify that the style is compatible with current society practice.
(And of course, although it should go without saying, I am not a lawyer, and the above should not be taken as legal guidance.)