Minor cleanup and texture update

graphics/src/rse_graphics.c

@@ -36,7 +36,7 @@ void rse_graphics_test_function(void)
     rse_err_t status = RSE_ERROR_NO_ERROR;
     uint16_t tex_id_2 = 0;
 
-    status = rse_load_texture("../../test_image.png", &tex_id_2);
+    status = rse_load_texture("../../test_image.jpg", &tex_id_2);
     if (status != RSE_ERROR_NO_ERROR) {
         LOGE("Failed to do something. Check error messages");
         return;