fix: Apply image format when saving file in ImagickDriver (#268)

Certain functions like `resizeCanvas`, `overlay` actually re-assign
the `image` property, thus "losing" the format if it was set prior to
calling those transformations.

This can be avoided by ensuring `setFormat()` on the Imagick image(s)
is only called prior to saving the image, at which point the format
will always be correct when saving the file.

To do this, the format is stored as a property on the driver object.
(The GD driver already does it the same way, so I just made a few
adjustments to bring this driver in line with the GD driver.)

src/Drivers/Imagick/ImagickDriver.php

@@ -39,6 +39,8 @@ class ImagickDriver implements ImageDriver
 
     protected Imagick $image;
 
+    protected ?string $format = null;
+
     protected array $exif = [];
 
     protected string $originalPath;
@@ -256,19 +258,27 @@ public function save(?string $path = null): static
         if (! $path) {
             $path = $this->originalPath;
         }
-
-        $extension = pathinfo($path, PATHINFO_EXTENSION);
-
+        if (is_null($this->format)) {
+            $format = pathinfo($path, PATHINFO_EXTENSION);
+        } else {
+            $format = $this->format;
+        }
         $formats = Imagick::queryFormats('*');
-
         if (in_array('JPEG', $formats)) {
             $formats[] = 'JFIF';
         }
-
-        if (! in_array(strtoupper($extension), $formats)) {
-            throw UnsupportedImageFormat::make($extension);
+        if (! in_array(strtoupper($format), $formats)) {
+            throw UnsupportedImageFormat::make($format);
         }
 
+        foreach ($this->image as $image) {
+            if (strtoupper($format) === 'JFIF') {
+                $image->setFormat('JPEG');
+            } else {
+                $image->setFormat($format);
+            }
+        }
+
         if ($this->isAnimated()) {
             $image = $this->image->deconstructImages();
             $image->writeImages($path, true);
@@ -279,6 +289,7 @@ public function save(?string $path = null): static
         if ($this->optimize) {
             $this->optimizerChain->optimize($path);
         }
+        $this->format = null;
 
         return $this;
     }
@@ -618,9 +629,7 @@ public function quality(int $quality): static
 
     public function format(string $format): static
     {
-        foreach ($this->image as $image) {
-            $image->setFormat($format);
-        }
+        $this->format = $format;
 
         return $this;
     }