Alt tag for src='blank.gif' on lazy load images

[friendoffood]

I didn't find an answer on a search on this, so maybe someone here has faced this before.

I am loading 20 images that are in the viewport and a bit below.  The next 80 images I want to 'lazy-load'.  They therefore are seen by the bot as a blank.gif file.  However, I would like to get some credit for them by giving a description in the alt tag.  Is that a no-no?  If not, do they all have to be the same alt description since the src name is the same?  I don't want to mess things up with Google by being too aggressive, but at the same time those are valid images once they are lazy loaded, so would like to get some credit for them.

Thanks!  Ted

[Martijn_Scheijbeler]

Hi Ted, to be honest we do this and I don't see any big issues why we wouldn't do it. The placeholder image will probably get some more credits than usual. But the images we lazy load are loaded via JS and as Google says it can understand JS they should be able to get how we use it (too much assumptions I know, but I have more things to worry about ;-)).

[friendoffood]

Martijn,  thanks for your response.  I could see Google saying that on a given page the same source image shouldn't have more than one alt description, and either penalizing such or just picking one of them or ignoring it altogether.  It's the penalty I'm concerned with, of course. . But, I can also see that if they are seeing a blank.gif for the source and some code related to lazy loading they may go ahead and give credit to each alt as though a real src was loaded--and maybe even tying it to the real src image name for image search.  Just looking for a bit more feedback from real-world experience first..

Has anyone else worked with this and determined if it is a pro or con?