Update how image resources are loaded/validated

platform/ios/src/MGLMapView.mm

@@ -467,7 +467,7 @@ - (void)commonInit
 
  // setup logo bug
  //
- UIImage *logo = [MGLMapView resourceImageNamed:@"mapbox.png"];
+ UIImage *logo = [MGLMapView resourceImageNamed:@"mapbox"];
  _logoView = [[UIImageView alloc] initWithImage:logo];
  _logoView.accessibilityTraits = UIAccessibilityTraitStaticText;
  _logoView.accessibilityLabel = NSLocalizedStringWithDefaultValue(@"LOGO_A11Y_LABEL", nil, nil, @"Mapbox", @"Accessibility label");
@@ -616,7 +616,7 @@ - (void)createGLView
 
 - (UIImage *)compassImage
 {
- UIImage *scaleImage = [MGLMapView resourceImageNamed:@"Compass.png"];
+ UIImage *scaleImage = [MGLMapView resourceImageNamed:@"Compass"];
  UIGraphicsBeginImageContextWithOptions(scaleImage.size, NO, [UIScreen mainScreen].scale);
  [scaleImage drawInRect:{ CGPointZero, scaleImage.size }];
 
@@ -5290,18 +5290,17 @@ - (void)updateCompass
 
 + (UIImage *)resourceImageNamed:(NSString *)imageName
 {
- NSString *extension = imageName.pathExtension.length ? imageName.pathExtension : @"png";
- NSBundle *bundle = [NSBundle mgl_frameworkBundle];
- NSString *path = [bundle pathForResource:imageName.stringByDeletingPathExtension
- ofType:extension
- inDirectory:bundle.mgl_resourcesDirectory];
- if ( ! path)
+ UIImage *image = [UIImage imageNamed:imageName
+ inBundle:[NSBundle mgl_frameworkBundle]
+ compatibleWithTraitCollection:nil];
+
+ if ( ! image)
  {
  [NSException raise:@"Resource not found" format:
  @"The resource named “%@” could not be found in the Mapbox framework bundle.", imageName];
  }
 
- return [UIImage imageWithContentsOfFile:path];
+ return image;
 }
 
 - (BOOL)isFullyLoaded