"I hate the way you have to list the source from ancestry when there are no page numbers in the books! I don't consider an image number as a good part of a source citation."
Yes, an image number should not be considered a primary part of a source citation. It can be included (and I often do so) but only as secondary information.
Here is what I do when citing births, marriages or deaths from volumes that have no page number. I count the number of pages from the page having the first entries of the year in which the event happened. OK, that's not too clear, here is an example. Lets say I want to record a birth from 1781. First, I find the page containing the January births of 1781 - that's "page 1". Then I start counting pages (*not* images), flipping forward through the digital images (or scrolling the microfilm reel) until I reach the page containing my birth entry. Lets say that was on "page 3". I then cite the record as: "No page number (3rd page of 1781)". Sometimes, if there are births, deaths and/or marriages intermingled in the same volume, I will write "(3rd page of 1781 births)", just to be 100% clear. Or, if all the births for 1781 happen to be on one page, maybe I will shorten it to "No page number (1781 births)".
My method may be time consuming and a bit cumbersome, and some will argue that the "No page number" bit is unnecessary and confusing, but I think the basic idea is sound. I've written hundreds of citations in this form and I've always been able to quickly relocate an entry, even if I wrote the citation years earlier.
You can use my method or not, makes no difference to me. However you do it, the point is, a properly written source citation should make it straightforward for another researcher to unambiguously locate the same record, no matter what medium the volume is in (e.g., digitized image, microfilm or even the original book).