diff --git a/Computer Architecture/assets/cache-memories.png b/Computer Architecture/assets/cache-memories.png
index c5ed338..237dede 100644
Binary files a/Computer Architecture/assets/cache-memories.png and b/Computer Architecture/assets/cache-memories.png differ
diff --git a/Computer Architecture/assets/compilation-system-overview.png b/Computer Architecture/assets/compilation-system-overview.png
index 6ac7445..f01f0da 100644
Binary files a/Computer Architecture/assets/compilation-system-overview.png and b/Computer Architecture/assets/compilation-system-overview.png differ
diff --git a/Computer Architecture/assets/execution-of-hello.png b/Computer Architecture/assets/execution-of-hello.png
index bf748cb..9c06eec 100644
Binary files a/Computer Architecture/assets/execution-of-hello.png and b/Computer Architecture/assets/execution-of-hello.png differ
diff --git a/Computer Architecture/assets/full-memory-pyramid.png b/Computer Architecture/assets/full-memory-pyramid.png
index 392fed0..cb23f61 100644
Binary files a/Computer Architecture/assets/full-memory-pyramid.png and b/Computer Architecture/assets/full-memory-pyramid.png differ
diff --git a/Computer Architecture/assets/hello-c-ascii.png b/Computer Architecture/assets/hello-c-ascii.png
index 8a295d8..02a8aa6 100644
Binary files a/Computer Architecture/assets/hello-c-ascii.png and b/Computer Architecture/assets/hello-c-ascii.png differ
diff --git a/Computer Architecture/assets/loading-hello-executable.png b/Computer Architecture/assets/loading-hello-executable.png
index 112efc2..cab6810 100644
Binary files a/Computer Architecture/assets/loading-hello-executable.png and b/Computer Architecture/assets/loading-hello-executable.png differ
diff --git a/Computer Architecture/assets/os-abstractions.png b/Computer Architecture/assets/os-abstractions.png
index a9dce9b..adb1a40 100644
Binary files a/Computer Architecture/assets/os-abstractions.png and b/Computer Architecture/assets/os-abstractions.png differ
diff --git a/Computer Architecture/assets/reading-hello-command.png b/Computer Architecture/assets/reading-hello-command.png
index 3c3c8e9..528eba5 100644
Binary files a/Computer Architecture/assets/reading-hello-command.png and b/Computer Architecture/assets/reading-hello-command.png differ
diff --git a/Computer Architecture/assets/typical-hwd-org.png b/Computer Architecture/assets/typical-hwd-org.png
index 152eb34..957fdcd 100644
Binary files a/Computer Architecture/assets/typical-hwd-org.png and b/Computer Architecture/assets/typical-hwd-org.png differ
diff --git a/Cryptography/assets/alice-bob-oscar-basic.png b/Cryptography/assets/alice-bob-oscar-basic.png
index 4ce8c43..b8b9ecd 100644
Binary files a/Cryptography/assets/alice-bob-oscar-basic.png and b/Cryptography/assets/alice-bob-oscar-basic.png differ
diff --git a/Cryptography/assets/alice-bob-oscar-sym-key.png b/Cryptography/assets/alice-bob-oscar-sym-key.png
index 6597ab8..8983e04 100644
Binary files a/Cryptography/assets/alice-bob-oscar-sym-key.png and b/Cryptography/assets/alice-bob-oscar-sym-key.png differ
diff --git a/Cryptography/assets/cryptanalysis-overview.png b/Cryptography/assets/cryptanalysis-overview.png
index 37f57a1..6cdeeaf 100644
Binary files a/Cryptography/assets/cryptanalysis-overview.png and b/Cryptography/assets/cryptanalysis-overview.png differ
diff --git a/Cryptography/assets/cryptology-tree.png b/Cryptography/assets/cryptology-tree.png
index 2019d11..31ee53f 100644
Binary files a/Cryptography/assets/cryptology-tree.png and b/Cryptography/assets/cryptology-tree.png differ
diff --git a/Cryptography/assets/english-letter-freqs.png b/Cryptography/assets/english-letter-freqs.png
index 999501b..bd975cf 100644
Binary files a/Cryptography/assets/english-letter-freqs.png and b/Cryptography/assets/english-letter-freqs.png differ
diff --git a/Cryptography/assets/sub-cipher-abba-eg.png b/Cryptography/assets/sub-cipher-abba-eg.png
index c35bebb..9fd2a74 100644
Binary files a/Cryptography/assets/sub-cipher-abba-eg.png and b/Cryptography/assets/sub-cipher-abba-eg.png differ
diff --git a/Networks/assets/protocol-basic-analogy.png b/Networks/assets/protocol-basic-analogy.png
index d42eaff..9573612 100644
Binary files a/Networks/assets/protocol-basic-analogy.png and b/Networks/assets/protocol-basic-analogy.png differ