diff --git a/docs/cookbook.md b/docs/cookbook.md
index 29201b9b..06941a97 100644
--- a/docs/cookbook.md
+++ b/docs/cookbook.md
@@ -283,8 +283,7 @@ as little as possible:
 ocrmypdf --pages 1 --output-type pdf --optimize 0 input.pdf output.pdf
 ```
 
-Redo existing OCR
------------------
+## Redo existing OCR
 
 To redo OCR on a file OCRed with other OCR software or a previous
 version of OCRmyPDF and/or Tesseract, you may use the `--redo-ocr`
@@ -330,8 +329,7 @@ OCR quality will suffer if the resolution of input images is not correct
 (since the range of pixel sizes that will be checked for possible fonts
 will also be incorrect).
 
-PDF optimization
-----------------
+## PDF optimization
 
 By default OCRmyPDF will attempt to perform lossless optimizations on
 the images inside PDFs after OCR is complete. Optimization is performed
@@ -339,40 +337,9 @@ even if no OCR text is found.
 
 The `--optimize N` (short form `-O`) argument controls optimization,
 where `N` ranges from 0 to 3 inclusive, analogous to the optimization
-levels in the GCC compiler.
+levels in the GCC compiler. `-O1` is the default.
 
-:::{list-table}
----
-widths: auto
-header-rows: 1
----
-
-*   - Level
-    - Comments
-*   - <nobr>``--optimize=0``</nobr>
-    - Disables optimization.
-*   - <nobr>``--optimize 1``</nobr>
-    - Enables lossless optimizations, such as transcoding images to more
-        efficient formats. Also compress other uncompressed objects in the
-        PDF and enables the more efficient "object streams" within the PDF.
-        (If ``--jbig2-lossy`` is issued, then lossy JBIG2 optimization is used.
-        The decision to use lossy JBIG2 is separate from standard optimization
-        settings.)
-*   - <nobr>``--optimize 2``</nobr>
-    - All of the above, and enables lossy optimizations and color quantization.
-*   - <nobr>``--optimize 3``</nobr>
-    - All of the above, and enables more aggressive optimizations and targets lower image quality.
-:::
-
-Optimization is improved when a JBIG2 encoder is available and when
-`pngquant` is installed. If either of these components are missing, then
-some types of images cannot be optimized.
-
-The types of optimization available may expand over time. By default,
-OCRmyPDF compresses data streams inside PDFs, and will change
-inefficient compression modes to more modern versions. A program like
-`qpdf` can be used to change encodings, e.g. to inspect the internals
-for a PDF.
+For further details, see the section on [PDF optimization](optimizer).
 
 ```bash
 ocrmypdf --optimize 3 in.pdf out.pdf  # Make it small
diff --git a/docs/optimizer.md b/docs/optimizer.md
index aeda78a8..5c7b28cd 100644
--- a/docs/optimizer.md
+++ b/docs/optimizer.md
@@ -25,17 +25,23 @@ header-rows: 1
   - Disable most optimizations.
 * - ``--optimize 1`` (default)
   - ``-O1``
-  - Safe and lossless optimizations.
+  - Enables lossless optimizations, such as transcoding images to more
+      efficient formats. Also compress other uncompressed objects in the
+      PDF and enables the more efficient "object streams" within the PDF.
+      (If ``--jbig2-lossy`` is issued, then lossy JBIG2 optimization is used.
+      The decision to use lossy JBIG2 is separate from standard optimization
+      settings.)
 * - ``--optimize 2``
   - ``-O2``
-  - Safe and lossy optimizations.
+  - All of the above, and enables lossy optimizations and color quantization.
 * - ``--optimize 3``
   - ``-O3``
-  - Aggressive lossy optimizations.
+  - All of the above, and enables more aggressive optimizations and targets lower
+      image quality.
 :::
 
 The exact type of optimizations performed will vary over time, and
-depend on the availability of third-party tools.
+depend on what third party tools are installed.
 
 Despite optimizations, OCRmyPDF might still increase the overall file
 size, since it must embed information about the recognized text, and
@@ -83,8 +89,13 @@ objects more aggressively.
 
 ## Lossy optimizations
 
-At optimization level `-O2` and `-O3`, OCRmyPDF will some attempt lossy
-image optimization.
+At optimization level `-O1`, `-O2` and `-O3`, OCRmyPDF will some attempt
+loss image optimization.
+
+If Ghostscript is used to create a PDF/A (the default), Ghostscript will
+optimize some images by converting them to JPEG, which are lossy. If
+`--output-type pdf` is used, there are no lossy optimizations. Ghostscript's
+JPEG conversion is quite safe.
 
 If `pngquant` is installed, OCRmyPDF will use it to perform quantize
 paletted images to reduce their size.