Magnifying the Help documents without magnifying the images therein

Question

In Mathematica's Option Inspector I set the notebook magnification factor to be larger than 1, for example 1.12 ("Notebook Options"->"Display Options"). Accordingly contents of the Documentation Center are all magnified including the images which now look like this:

As shown above the lines in the images after magnification are in a zigzag fashion and ugly to look at.

So is there a way to set the notebook magnification factor above 1, without affecting the images (that is, without magnifying the images)?

Answer 1

If you look at the BoxForm of the rasterized output in the Documentation Center by selecting it and pressing Ctrl+Shift+E, you'll see that GraphicsBox containing the rasterized plot has the option DefaultBaseStyle -> "ImageGraphics". So we can control magnification of such elements by adding to the Notebook's private stylesheet the following definition for the style "ImageGraphics":

Cell[StyleData["ImageGraphics"], Magnification->1]

This works great for any ordinary Notebook but applying this option to the Documentation Notebooks is tricky since they have the option Editable -> False and it isn't recommended to edit them. By default they have set StyleDefinitions -> FrontEnd`FileName[{"Wolfram"}, "Reference.nb", CharacterEncoding -> "UTF-8"] and hence their styles are defined in the stylesheet "Reference.nb" located in the folder

FileNameJoin[{$InstallationDirectory, "SystemFiles", "FrontEnd", "StyleSheets", "Wolfram"}]

You can make a copy of this stylesheet, remove the Editable -> False and Saveable -> False options and then edit the "ImageGraphics" style (located in the "FormatType and Automatic Styles" section). Then you can copy this file to the following folder and then restart Mathematica:

FileNameJoin[{$UserBaseDirectory, "SystemFiles", "FrontEnd", "StyleSheets", "Wolfram"}]  

Stylesheets from this folder have higher priority than from the previous because it is located earlier in the StyleSheetPath global FrontEnd setting:

AbsoluteOptions[$FrontEnd, StyleSheetPath]

{StyleSheetPath -> {FrontEnd`FileName[{$UserBaseDirectory, "Autoload", _, 
     "FrontEnd", "StyleSheets"}], 
   FrontEnd`FileName[{$UserBaseDirectory, "Applications", _, "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$BaseDirectory, "Autoload", _, "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$BaseDirectory, "Applications", _, "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$InstallationDirectory, "AddOns", "Autoload", _, 
     "FrontEnd", "StyleSheets"}], 
   FrontEnd`FileName[{$InstallationDirectory, "AddOns", "Applications", _, 
     "FrontEnd", "StyleSheets"}], 
   FrontEnd`FileName[{$UserBaseDirectory, "SystemFiles", "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$BaseDirectory, "SystemFiles", "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$InstallationDirectory, "Configuration", "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{$InstallationDirectory, "SystemFiles", "Components", _, 
     "FrontEnd", "StyleSheets"}], 
   FrontEnd`FileName[{$InstallationDirectory, "SystemFiles", "FrontEnd", 
     "StyleSheets"}], 
   FrontEnd`FileName[{"C:\\Program Files\\Wolfram Research\\Mathematica\\10.4\
\\SystemFiles\\Components\\MUnit\\FrontEnd", "StyleSheets"}, 
    "PacletManager" -> True]}}

---

All the above operations can be completely automatized:

CreateDirectory[
 FileNameJoin[{$UserBaseDirectory, "SystemFiles", "FrontEnd", "StyleSheets", 
   "Wolfram"}]];
CopyFile @@ (FileNameJoin[{#, "SystemFiles", "FrontEnd", "StyleSheets", 
       "Wolfram", 
       "Reference.nb"}] & /@ {$InstallationDirectory, $UserBaseDirectory});
nb = NotebookOpen[
   FileNameJoin[{$UserBaseDirectory, "SystemFiles", "FrontEnd", "StyleSheets",
      "Wolfram", "Reference.nb"}]];
SetOptions[nb, {Editable -> True, Saveable -> True}];

NotebookFind[nb, "ImageGraphics"];
cell = NotebookRead[nb];
If[TrueQ[First@cell === StyleData["ImageGraphics"]], 
 NotebookWrite[nb, Append[cell, Magnification -> 1], All]; NotebookSave[nb], $Failed]

(then restart Mathematica).

I have tested the above and it works! Screenshot:

Answer 2

The solution suggested in the comments works too:

SetOptions[$FrontEnd, GraphicsBoxOptions -> {BaseStyle -> Magnification -> 1}]

But of course this affects all Notebooks, not only the Documentation Notebooks. And moreover it affects not only raster graphics but all 2D graphics in the Notebooks...

For reverting to the defaults one should evaluate

SetOptions[$FrontEnd, GraphicsBoxOptions -> {BaseStyle -> Inherited}]