13. Custom Operator Logo

1. Naming and priority 
 Allowed naming patterns: 
 
 generic logo: OPERATOR.bmp or OPERATOR.png 
 type-specific logo: OPERATOR-ICAOTYPE.bmp or OPERATOR-ICAOTYPE.png 
 
 Runtime priority: 
 
 type-specific logo is preferred, 
 generic logo is fallback. 
 
 2. Validation rules 
 
 file type must be .bmp or .png , 
 file size limit is 2 MB , 
 required aspect ratio is 17:4 , 
 template size is 85x20 , 
 if image has valid ratio but larger dimensions, explicit downscale confirmation is required, 
 operator code accepts A-Z , 0-9 , @ , . , _ , + , - ( 2-40 chars), 
 optional ICAO type accepts A-Z , 0-9 ( 2-12 chars). 
 
 3. Overwrite behavior 
 
 if target logo already exists and overwrite=false , upload returns conflict, 
 when saving one extension, counterpart extension for same key is removed to keep deterministic lookup. 
 
 4. Storage and metadata 
 
 files are stored in Images/AirlineLogos , 
 upload metadata is tracked in custom-operator-flags.json , 
 after upload/delete, OperatorFlagsList.csv is synchronized, 
 resource service is reloaded immediately.