Fix std without image feature

Author: Systemcluster

.github/workflows/tests.yml

@@ -56,6 +56,9 @@ jobs:
       - name: Check no-default-features
         run: cargo check --no-default-features
 
+      - name: Check no-default-features with std
+        run: cargo check --no-default-features --features std
+
   tests:
 
     name: Tests

src/errors.rs

@@ -5,7 +5,7 @@ use core::str::Utf8Error;
 
 #[cfg(feature = "images")]
 use image::ImageError;
-#[cfg(feature = "images")]
+#[cfg(feature = "std")]
 use std::io::Error as IOError;
 
 /// Error that can occur when reading and parsing bytes.