A HSG ( hysterosalpingogram, X-ray of the uterus and tubes is a very useful test to check if the uterine cavity is normal and the fallopian tubes are open. In this series of X-rays, you can clearly see the dye entering the cavity; filling the cavity; and then entering the tubes, filling them, and then spilling out of the terminal ends. This is a normal HSG, showing that the tubes are patent ( normal fill and spill). Some of the plates are white on black , and this is because the radiologist has manipulated the image. You can also see that the dye seems to have collected in one place - what is called a loculation.
The problem is that most X-ray clinics do a very poor job at taking a HSG , because they try to cut corners. Many radiologists are not comfortable doing a vaginal examination, and are quite clumsy at performing the HSG. Even worse, they only take 2-3 films, and don't bother to take a delayed film, which means it becomes very hard to interpret the images correctly. And because it's such a painful procedure, we don't want to repeat it again !
Also, please understand the limitations of a HSG. We can make out if the tubes are open, but we cannot determine if they are working properly or not. Similarly, we cannot determine if there are adhesions outside the tubes - and we shouldn't be trying to guess either !
You can read more about the HSG at http://www.drmalpani.com/knowledge-center/articles/hysterosalpingogram.