diff --git a/src/image.rs b/src/image.rs
index bde4e6b..d202f37 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -52,8 +52,15 @@ impl Image {
         self.pixels = pixels;
     }
 
-    fn from_str(str: &str) -> Result<Image, crate::Error> {
+    fn from_str(str: &str) -> Result<(Image, Vec<crate::Error>), crate::Error> {
+        let mut warnings = Vec::new();
+
+        if str.contains("NaN") {
+            warnings.push(crate::Error::Image);
+        }
+
         let string = str.trim().replace("NaN", "0");
+
         let lines: Vec<&str> = string.lines().collect();
         let dimension = lines.len();
         let mut pixels: Vec<u8> = Vec::new();
@@ -61,11 +68,16 @@ impl Image {
         for line in lines {
             let line = &line[..dimension];
             for char in line.chars().into_iter() {
+                // todo push warning on integers other than 0/1
                 pixels.push(match char {'1' => 1, _ => 0});
             }
         }
 
-        Ok(Image { pixels })
+        if [64, 256].contains(&pixels.len()) {
+            Ok((Image { pixels }, warnings))
+        } else {
+            Err(crate::Error::Image)
+        }
     }
 }
 
@@ -93,7 +105,7 @@ pub fn animation_frames_from_str(str: &str) -> Vec<Image> {
         .split('>')
         .collect::<Vec<&str>>()
         .iter()
-        .map(|&frame| Image::from_str(frame).unwrap())
+        .map(|&frame| Image::from_str(frame).unwrap().0)
         .collect()
 }
 
@@ -104,7 +116,7 @@ mod test {
 
     #[test]
     fn image_from_string() {
-        let output = Image::from_str(include_str!("test-resources/image")).unwrap();
+        let (output, _) = Image::from_str(include_str!("test-resources/image")).unwrap();
 
         let expected = Image {
             pixels: vec![
@@ -144,7 +156,7 @@ mod test {
     /// check that these extraneous pixels are stripped out
     #[test]
     fn image_out_of_bounds() {
-        let output = Image::from_str(include_str!("test-resources/image-oob")).unwrap();
+        let (output, _) = Image::from_str(include_str!("test-resources/image-oob")).unwrap();
 
         let expected = Image {
             pixels: vec![