An image can be in screening for a day or two waiting for screeners opinions, Its more the images with questionable motives which require quite a few opinions before being rejected/accepted.
Regarding a normal HQ
image it can take up to few hours to screen if not more , Earlier in the day when I did some screening there were almost 200 photos in HQ
queue which had been viewed by at least one screener and waiting another screener(s) opinion before being decided on, So it could take at least 2-4 screeners to screen those images as some of the new screeners in training focus on the HQ
Queue while the more experienced screeners either do a few batches of HQ
images or focus more on the normal queue. We try to keep at least 100-150 images in HQ
queue so depends what is needed.
Time zones do play a factor so there probably will not be much screening done in next few hours as Its night time in USA/Canada and Early morning in European time zones where most of the screening team are from.
The data of images in the queue is pretty much up to date.