This is related to your book, Gideros Mobile Game Development, which I purchased a short time ago.
I'm trying to implement suffixes for different image sizes, which you mention on page 23. I couldn't get it to work following the example in the book. The book uses an underscore before the @ symbol and this wasn't working for me. I posted to the forum under the title "Why aren't my suffixes working?" and one of the responses was to eliminate the underscore. I did this and it worked, at least partially. I'm still trying to get it to work comletely.
I know the book is a bit old. Has Gideros undergone a change that eliminated using the underscore or was this an erroe in the book?