COURSE ICONS NEEDED:

- open_water.png - Open Water Diver course icon
- advanced.png - Advanced Open Water course icon  
- marine_bio.png - Marine Biology Specialty course icon
- wreck.png - Wreck Diver Specialty course icon
- deep_diving.png - Deep Diver Specialty course icon

Requirements:
- PNG format with transparency
- 64x64 pixels minimum
- Simple, clear design
- Diving/underwater theme