Add Photographer metadata preset and improve quality descriptions

Add Photographer mode to metadata step that keeps copyright and camera
model while stripping GPS and software data. Improve compress quality
descriptions with estimated file size reduction percentages.

pixstrip-gtk/src/steps/step_compress.rs

@@ -187,10 +187,10 @@ pub fn build_compress_page(state: &AppState) -> adw::NavigationPage {
 
 fn quality_description(val: u32) -> String {
     match val {
-        1 => "Web Optimized - smallest files, noticeable quality loss. Best for thumbnails.".into(),
-        2 => "Low - small files, some quality loss. Good for email attachments.".into(),
-        3 => "Medium - good balance of quality and size. Recommended for most uses.".into(),
-        4 => "High - large files, minimal quality loss. Good for printing.".into(),
-        _ => "Maximum - largest files, best possible quality. Archival use.".into(),
+        1 => "Web Optimized - ~70-80% smaller files. Noticeable quality loss. Best for thumbnails and web previews.".into(),
+        2 => "Low - ~50-60% smaller files. Some visible quality loss. Good for email attachments and quick sharing.".into(),
+        3 => "Medium - ~30-40% smaller files. Good balance of quality and size. Recommended for most uses.".into(),
+        4 => "High - ~15-25% smaller files. Minimal quality loss. Good for printing and high-quality output.".into(),
+        _ => "Maximum - ~5-10% smaller files. Best possible quality, largest files. Archival and professional use.".into(),
     }
 }