Reveal Current Desktop Picture In Finder

main.m

// Build with compiler flag `-lsqlite3`.

#import <Foundation/Foundation.h>
#import <AppKit/AppKit.h>
#import <sqlite3.h>

NSString *getDesktopImagePath() {
	NSFileManager *fileManager = [NSFileManager defaultManager];
	
	NSURL *imageURL = [[NSWorkspace sharedWorkspace] desktopImageURLForScreen:[NSScreen mainScreen]];
	NSString *urlPath = [imageURL path];
	
	// Check if it's a file that exists
	BOOL isDirectory;
	BOOL exists = [fileManager fileExistsAtPath:urlPath isDirectory:&isDirectory];
	
	if (exists) {
		if (!isDirectory) {
			return urlPath;
		}

		// Use SQLite to get the filename
		NSString *appSup = [NSSearchPathForDirectoriesInDomains(
			NSApplicationSupportDirectory,
			NSUserDomainMask,
			YES
		) firstObject];
		NSString *dbPath = [appSup stringByAppendingPathComponent:@"Dock/desktoppicture.db"];
		
		sqlite3 *database;
		if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) {
			const char *sql = "SELECT * FROM data";
			sqlite3_stmt *sel;
			
			if(sqlite3_prepare_v2(database, sql, -1, &sel, NULL) == SQLITE_OK) {
				NSMutableArray *sqliteData = [NSMutableArray array];
				
				while(sqlite3_step(sel) == SQLITE_ROW) {
					NSString *data = [NSString stringWithUTF8String:(char *)sqlite3_column_text(sel, 0)];
					[sqliteData addObject:data];
				}
				
				if ([sqliteData count] > 0) {
					NSString *imageFileName = [sqliteData lastObject];
					NSString *imagePath = [urlPath stringByAppendingPathComponent:imageFileName];
					if ([fileManager fileExistsAtPath:imagePath]) {
						sqlite3_close(database);
						return imagePath;
					}

				}
			}
			sqlite3_close(database);
		}
	}
	return nil;
}

int main(int argc, char *argv[]) {
	@autoreleasepool {
		NSString *imagePath = getDesktopImagePath();
		
		if (imagePath) {
			[[NSWorkspace sharedWorkspace] selectFile:imagePath inFileViewerRootedAtPath:@""];
		} else {
			NSLog(@"Could not find current desktop picture.");
		}
	}
}

Code to get the filename from the sqlite database is from https://stackoverflow.com/a/31014090/6358721