chore: replace 5 English blog covers

blog/2025-09-26-Analysis-of-PG-18-Key-New-Features/index.md

@@ -4,7 +4,7 @@ title: In-Depth Analysis of PostgreSQL 18 Key New Features
 authors: [official]
 authorTwitter: IvorySql
 category: PostgreSQL
-image: img/blog/covers/pg18-features.svg
+image: img/blog/covers/pg18-features-en.png
 tags: [IvorySQL, Database, UUIDv7, PostgreSQL, I/O, OAuth]
 ---
 

blog/2026-02-10-ivorysql-5.0-oracle-to-postgresql-migration/index.md

@@ -3,7 +3,7 @@ slug: ivorysql-5.0-oracle-to-postgresql-migration
 title: IvorySQL 5.0+ - a game changer for Oracle to PostgreSQL transitions
 authors: [Yasir Hussain Shah]
 category: IvorySQL
-image: img/blog/covers/oracle-migration.svg
+image: img/blog/covers/oracle-migration-en.png
 tags: [IvorySQL, Database, Oracle Compatible, PostgreSQL, migration]
 ---
 

blog/2026-07-06-oracle-compat-kernel/index.md

@@ -3,7 +3,7 @@ slug: oracle-compat-kernel
 title: "Why Can Oracle Run on PostgreSQL? The Answer Lies in the Kernel"
 authors: [ZhangChen]
 category: IvorySQL
-image: img/blog/covers/oracle-compat-kernel-en.svg
+image: img/blog/covers/oracle-compat-kernel-en.png
 tags: [IvorySQL, Oracle, PostgreSQL, Kernel, PL/iSQL, Migration]
 ---
 

blog/2026-07-08-ivorysql-agent/index.md

@@ -3,7 +3,7 @@ slug: ivorysql-agent
 title: "IvorySQL Agent: AI-Powered Database Management"
 authors: [Oreo Yang]
 category: IvorySQL
-image: img/blog/covers/ivorysql-agent-en.svg
+image: img/blog/covers/ivorysql-agent-en.png
 tags: [IvorySQL, AI, Agent, RAG, NL2SQL, PostgreSQL]
 ---