They're not common, but I've been in a couple of shops with multiple large-format printers. They are basically giant ink-jet printers.
Maybe Hezbollah bought several of them to make posters for demonstrations?
Also, it is a common practice to apply a laminate overcoat to the paper to make them more durable. It might be possible to interpose elements between the laminate and the paper.
So, You would need the poster or samples of it to tell for sure.
"..Since I do banners like this for a living, I can tell you it take more than a few hours depending on the equipment. A banner that large can be done one of two ways. With a grant format printer. It would probably take about 3-4 hours to print, then hours more to sew and grommet so it could hung. It would have to be Made of heavy duty material or one that was reinforced or the sheer weight would rip it apart.
The other way it to use a smaller series of machines all color calibrated and produce sections. At that point they would have to be stretch the length of the banner ( read large facility) and sewn together. Additional support would go on the tops and bottoms.
In short if it was related Qana and went up within two hours- four hours, it was done prior to the bomb hitting. No other way. Just putting an image together that large on a computer with Type would take a few hours.
Then color tests, proofs and finally printing. That would be an all day affair for most print houses even with a grand format printer. The cost would be in the thousands.
Then you would have to transport it..."