I am using GNOME, with Nautilus as its file manager.

I have installed the nautilus-image-converter plugin, to give me options to resize and rotate images from the context menu in Nautilus.

This is really useful, especially for posting in the fediverse, since I typically scale images down to <500kB.

By default, the plugin resizes images to 50% of their original size, and I prefer 25%.

The plugin does not have a preferences or settings pane, but you can change the default, by editing /usr/share/nautilus-image-converter/nautilus-image-resize.ui.

You want to change <property name="value">50</property> to <property name="value">25</property>, or whatever new default you want.

As a diff:

   <object class="GtkAdjustment" id="adjustment1">
     <property name="lower">1</property>
     <property name="upper">100</property>
-    <property name="value">50</property>
+    <property name="value">25</property>
     <property name="step_increment">1</property>
     <property name="page_increment">10</property>
   </object>

And that is it.

It survives a reboot, but I’ve no idea if it will survive an update of the plugin or not. But still easier to change it once in a while than to have to change it every time.