Change output bit depth to fixed size rgb8 (with alpha for png)

Signed-off-by: trivernis <trivernis@protonmail.com>

Cargo.toml

@@ -4,7 +4,7 @@ readme = "README.md"
 license = "Apache-2.0"
 authors = ["trivernis <trivernis@protonmail.com>"]
 description = "An image thumbnail creation library"
-version = "0.1.0"
+version = "0.2.0"
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

src/lib.rs

@@ -42,15 +42,16 @@ pub struct Thumbnail {
 impl Thumbnail {
     /// Writes the bytes of the image in a png format
     pub fn write_png<W: Write>(self, writer: &mut W) -> ThumbResult<()> {
-        self.inner.write_to(writer, ImageOutputFormat::Png)?;
+        let image = DynamicImage::ImageRgba8(self.inner.into_rgba8());
+        image.write_to(writer, ImageOutputFormat::Png)?;
 
         Ok(())
     }
 
     /// Writes the bytes of the image in a jpeg format
     pub fn write_jpeg<W: Write>(self, writer: &mut W, compression: u8) -> ThumbResult<()> {
-        self.inner
-            .write_to(writer, ImageOutputFormat::Jpeg(compression))?;
+        let image = DynamicImage::ImageRgb8(self.inner.into_rgb8());
+        image.write_to(writer, ImageOutputFormat::Jpeg(compression))?;
 
         Ok(())
     }