Cannot be much help in this. I never use picture fill.
If you can find that symbol somewhere in the ESRI fonts I would suggest trying to use that as the fill.
Now finding that symbol sounds intimidating. And it is. There are LOTS of fonts. (75)
What I did many years ago, and it took a little while to set up.
I created an Excel spreadsheet
Column A I made Ariel and populated the values with 33 through 255
Column B is also Ariel but I populated it with =CHAR(A2) and dragged it all the way down to 255. then to make it more streamlined I copied and pasted that new data into Notepad then copy and past it back to each cell was =char(number from column A)
For example cell B2 appears as !
Then I dragged all the cells from column B all the way to column BW
The the arduous part was changing the font in each column to the ESRI font. I have that many because I also have NISC fonts
I then printed it out on 11 x 17 paper and keep it in my cabinet. I have used this countless times to find a symbol I wanted
