I used a cute spiderweb graphic that I found on GraphicStock.com, and designed the print to be 24"x36". I had it printed as a 24"x36" engineering blueprint (you can do this at any copy place or office supply store) and it only cost about $3. This is a much less expensive way to make a huge black and white print than having a poster made. You can download the free print at the end of this post. I used black and white polkadot washi tape to secure it to the wall.
For the spiders, I found a bunch on GraphicStock.com by just typing "spider" in the search box, but the only one that Ella would touch was "the happy spider." That girl cracks me up. You can do a search and find the ones that will match your party's theme. There are spiders that are a lot spookier and even some that are different colors (a variety would be a great way to delineate what spider belongs to which child). GraphicStock offers a free 7 day trial, so you can download as many as you want for free.... or you could even design your own print if you find a spiderweb you like better. 2b1af7f3a8