diff --git a/examples/crop.rs b/examples/crop.rs
index f127ee2..5f294ff 100644
--- a/examples/crop.rs
+++ b/examples/crop.rs
@@ -15,7 +15,7 @@ fn main() {
         .split(&['x', '+'])
         .map(|s| u32::from_str(s).expect("Invalid number"))
         .collect();
-    let w = *parts.get(0).expect("witdh missing");
+    let w = *parts.first().expect("witdh missing");
     let h = *parts.get(1).expect("height missing");
     let x0 = *parts.get(2).unwrap_or(&0);
     let y0 = *parts.get(3).unwrap_or(&0);
diff --git a/examples/geotiff_dtm.rs b/examples/geotiff_dtm.rs
index ef2a5da..65a236b 100644
--- a/examples/geotiff_dtm.rs
+++ b/examples/geotiff_dtm.rs
@@ -95,7 +95,7 @@ fn main() {
     //     },
     // }
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((5000, 5000)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(16)));
     assert_eq!(tiff.origin(), Some([4250000.0, 2700000.0]));
diff --git a/examples/http_dtm.rs b/examples/http_dtm.rs
index 5a43fb4..0d88185 100644
--- a/examples/http_dtm.rs
+++ b/examples/http_dtm.rs
@@ -35,7 +35,7 @@ fn main() {
 
     let mut tiff = GeoTiffReader::open(img_reader).expect("Cannot create decoder");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((41999, 17610)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(32)));
     assert_eq!(tiff.origin(), Some([-20037506.48796601, 8401593.447238375]));
diff --git a/examples/img2ascii.rs b/examples/img2ascii.rs
index 239dfbc..9707451 100644
--- a/examples/img2ascii.rs
+++ b/examples/img2ascii.rs
@@ -54,7 +54,7 @@ fn main() -> std::io::Result<()> {
 }
 
 fn grey2ascii(luminance: f32) -> char {
-    assert!(luminance >= 0.0 && luminance <= 1.0);
+    assert!((0.0..=1.0).contains(&luminance));
     let ascii_scale = " .:-=+░▒▓▓";
     //let ascii_scale = " .:-=+*#%@";
     let char_index = ((ascii_scale.chars().count() - 1) as f32 * luminance).round();
diff --git a/src/geotiff.rs b/src/geotiff.rs
index bf8939b..2cad328 100644
--- a/src/geotiff.rs
+++ b/src/geotiff.rs
@@ -350,7 +350,7 @@ pub struct Pixels<'a, R: Read + Seek> {
     max_y: u32,
 }
 
-impl<'a, R: Read + Seek> Iterator for Pixels<'a, R> {
+impl<R: Read + Seek> Iterator for Pixels<'_, R> {
     type Item = (u32, u32, RasterValue);
 
     fn next(&mut self) -> Option<(u32, u32, RasterValue)> {
@@ -392,7 +392,7 @@ impl<'a, R: Read + Seek> Iterator for Pixels<'a, R> {
     }
 }
 
-impl<'a, R: Read + Seek> Pixels<'a, R> {
+impl<R: Read + Seek> Pixels<'_, R> {
     fn read_chunk(&mut self) {
         let chunk_index = self.dims.get_chunk_index(self.x, self.y, self.band_idx);
         self.row = chunk_index / self.dims.tiles_across() as u32;
@@ -497,10 +497,10 @@ impl TileAttributes {
         }
     }
     pub fn tiles_across(&self) -> usize {
-        (self.image_width + self.tile_width - 1) / self.tile_width
+        self.image_width.div_ceil(self.tile_width)
     }
     pub fn tiles_down(&self) -> usize {
-        (self.image_height + self.tile_length - 1) / self.tile_length
+        self.image_height.div_ceil(self.tile_length)
     }
     fn padding_right(&self) -> usize {
         (self.tile_width - self.image_width % self.tile_width) % self.tile_width
diff --git a/tests/geotiff.rs b/tests/geotiff.rs
index 232ecdb..44fc164 100644
--- a/tests/geotiff.rs
+++ b/tests/geotiff.rs
@@ -12,7 +12,7 @@ fn single_band() {
         BufReader::new(File::open("data/tiff/f32nan_data.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((128, 128)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(32)));
     assert_eq!(tiff.origin(), Some([0.0, 0.0]));
@@ -62,7 +62,7 @@ fn byte() {
     let img_file = BufReader::new(File::open("data/tiff/byte.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((20, 20)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(8)));
     assert_eq!(tiff.origin(), Some([440720.0, 3751320.0]));
@@ -78,7 +78,7 @@ fn float32() {
     let img_file = BufReader::new(File::open("data/tiff/float32.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((20, 20)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(32)));
     assert_eq!(tiff.origin(), Some([440720.0, 3751320.0]));
@@ -93,7 +93,7 @@ fn int16() {
     let img_file = BufReader::new(File::open("data/tiff/int16.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((20, 20)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(16)));
     assert_eq!(tiff.origin(), Some([440720.0, 3751320.0]));
@@ -109,7 +109,7 @@ fn int32() {
     let img_file = BufReader::new(File::open("data/tiff/int32.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((20, 20)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(32)));
     assert_eq!(tiff.origin(), Some([440720.0, 3751320.0]));
@@ -123,7 +123,7 @@ fn int32() {
 fn rgbsmall() {
     let img_file = BufReader::new(File::open("data/tiff/rgbsmall.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((50, 50)));
     assert_eq!(img.colortype, Some(tiff::ColorType::RGB(8)));
     assert_eq!(tiff.origin(), Some([-44.84032, -22.932584]));
@@ -220,7 +220,7 @@ fn small_world() {
     //         chunk_offsets: [
     //         ...
 
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((400, 200)));
     assert_eq!(img.colortype, Some(tiff::ColorType::RGB(8)));
     assert_eq!(tiff.origin(), Some([-180.0, 90.0]));
@@ -293,7 +293,7 @@ fn small_world_pct() {
     let img_file =
         BufReader::new(File::open("data/tiff/small_world_pct.tif").expect("Open image file"));
     let tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((400, 200)));
     assert_eq!(img.colortype, None);
     assert_eq!(tiff.origin(), Some([-180.0, 90.0]));
@@ -311,7 +311,7 @@ fn small_world_pct() {
 fn utm() {
     let img_file = BufReader::new(File::open("data/tiff/utm.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((512, 512)));
     assert_eq!(img.colortype, Some(tiff::ColorType::Gray(8)));
     assert_eq!(tiff.origin(), Some([440720.0, 3751320.0]));
@@ -414,7 +414,7 @@ fn rgb() {
     //         ],
     //     },
     // }
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((200, 200)));
     assert_eq!(img.colortype, Some(tiff::ColorType::RGB(8)));
     assert_eq!(tiff.origin(), Some([2747994.2968, 1205137.2435]));
@@ -470,7 +470,7 @@ fn rgb_bands() {
     let img_file =
         BufReader::new(File::open("data/tiff/sat_multiband.tif").expect("Open image file"));
     let mut tiff = GeoTiffReader::open(img_file).expect("Open Tiff");
-    let img = tiff.images().get(0).expect("Image info");
+    let img = tiff.images().first().expect("Image info");
     assert_eq!(img.dimensions, Some((200, 200)));
     assert_eq!(img.colortype, Some(tiff::ColorType::RGB(8)));
     assert_eq!(tiff.origin(), Some([2747994.2968, 1205137.2435]));