I'm not sure what your relationship or proximity to these designers is, but the best thing you can do to cure this is educate. It can be frustrating, sure, but

I'm not sure what your relationship or proximity to these designers is, but the best thing you can do to cure this is educate. It can be frustrating, sure, but making an effort to teach and explain what's wrong can make all the difference. Just because someone isn't top of the line doesn't mean they should be dismissed or frowned upon. Further, if it's something mission critical, just politely ask them if you can work on it to ensure its quality.