Adds image retrieval endpoint

src/main/kotlin/net/halfbinary/scavengerhuntapi/error/ExceptionHandler.kt

@@ -14,6 +14,7 @@ import org.springframework.web.bind.MethodArgumentNotValidException
 import org.springframework.web.bind.annotation.ExceptionHandler
 import org.springframework.web.bind.annotation.ResponseStatus
 import org.springframework.web.bind.annotation.RestControllerAdvice
+import org.springframework.web.method.annotation.MethodArgumentTypeMismatchException
 import org.springframework.web.multipart.MaxUploadSizeExceededException
 import java.net.SocketTimeoutException
 
@@ -96,6 +97,12 @@ class ExceptionHandler {
         return "Unable to connect. Try again later."
     }
 
+    @ExceptionHandler(MethodArgumentTypeMismatchException::class)
+    @ResponseStatus(HttpStatus.BAD_REQUEST)
+    fun argumentMismatchException(): String? {
+        return "Invalid parameter value."
+    }
+
     private fun simpleMap(key: String, value: String?): Map<String, String?> {
         return mapOf(Pair(key, value))
     }