Galleries have a wider business base than an artist, with a larger leeway for donation possibilities. However, even they have an eye on the bottom line, and seldom do they donate outright, unless it is to their largest clients.
There are many more ways galleries can have an impact on non-profit associations. Sometimes the gallery can approach the artist to donate on their own, or can pay the artist outright (usually 50 or 60% of the retail price) then donate their commission (50 or 40% of the retail price). The gallery can ask artists to donate the artwork and they will donate their commission, with two receipts being issued from the non-profit society; one to artist, one to gallery. Galleries can work in partnerships with other businesses such as a framing shop and all of the above would apply, plus the framer may donate a frame. And lastly, the charities would pay the gallery a percentage of the raised revenue.
The impact on the artist of losing a piece of saleable work and possible revenue is much reduced by the broader base of the gallery. And, regardless of the manner of funds being raised, the tax implications remain the same as those for an artist. Clean donations are preferred because they are solid and concrete evidence of funds exchanging hands between two parties.
The donation of fine art and other creative endeavours is big business for non profit organizations.