diff --git a/book/source/04-certificates.md b/book/source/04-certificates.md
index 65581d9..60b0123 100644
--- a/book/source/04-certificates.md
+++ b/book/source/04-certificates.md
@@ -32,7 +32,7 @@ An OpenPGP certificate (or "OpenPGP key") is a collection of an arbitrary number
 
 We sometimes collectively refer to component keys and identity information as the "components" of a certificate.
 
-```{figure} diag/OpenPGP\ Certificate.svg
+```{figure} diag/OpenPGP_Certificate.svg
 
 Typical components in an OpenPGP certificate
 ```
@@ -60,7 +60,7 @@ Component key representations that include private key material also contain met
 
 For each OpenPGP component key, an *OpenPGP fingerprint* can be derived from the combination of the public key material and creation timestamp (plus additional algorithm parameters, in the case of [ECDH Keys](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-10.html#name-algorithm-specific-part-for-ecd)):
 
-```{figure} diag/fingerprint.png
+```{figure} diag/Fingerprint.svg
 
 Every OpenPGP component key can be named by a fingerprint
 ```
@@ -92,7 +92,7 @@ In addition to the primary key, modern OpenPGP certificates usually contain a nu
 
 Subkeys have the same structure as the primary key, but they are used in a different role. Subkeys are cryptographically linked with the primary key (more on this below).
 
-```{figure} diag/with_subkeys.png
+```{figure} diag/Subkeys.png
 :name: Certificate with Subkeys
 :alt: Three component keys. The primary key is shown at the top. It can be used for certification. Below it, linked with arrows, are two more component keys, used as subkeys. They are marked as "for encryption" and "for signing", respectively.