diff --git a/safe-svg.php b/safe-svg.php
index 58a4a7f..073ba4a 100644
--- a/safe-svg.php
+++ b/safe-svg.php
@@ -444,9 +444,9 @@ public function fix_admin_preview( $response, $attachment, $meta ) {
 		 */
 		public function one_pixel_fix( $image, $attachment_id, $size, $icon ) {
 			if ( get_post_mime_type( $attachment_id ) === 'image/svg+xml' ) {
-				$dimensions = $this->svg_dimensions( $attachment_id );
+				$dimensions = $this->get_svg_dimensions( $attachment_id, $size );
 
-				if ( $dimensions ) {
+				if ( is_array( $dimensions ) && isset( $dimensions['height'], $dimensions['width'] ) ) {
 					$image[1] = $dimensions['width'];
 					$image[2] = $dimensions['height'];
 				} else {
@@ -499,23 +499,12 @@ public function load_custom_admin_style() {
 		 */
 		public function get_image_tag_override( $html, $id, $alt, $title, $align, $size ) {
 			$mime = get_post_mime_type( $id );
-
 			if ( 'image/svg+xml' === $mime ) {
-				if ( is_array( $size ) ) {
-					$width  = $size[0];
-					$height = $size[1];
-				// phpcs:ignore WordPress.CodeAnalysis.AssignmentInCondition.Found, Squiz.PHP.DisallowMultipleAssignments.FoundInControlStructure
-				} elseif ( 'full' === $size && $dimensions = $this->svg_dimensions( $id ) ) {
-					$width  = $dimensions['width'];
-					$height = $dimensions['height'];
-				} else {
-					$width  = get_option( "{$size}_size_w", false );
-					$height = get_option( "{$size}_size_h", false );
-				}
+				$dimensions = $this->get_svg_dimensions( $id, $size );
 
-				if ( $height && $width ) {
-					$html = str_replace( 'width="1" ', sprintf( 'width="%s" ', $width ), $html );
-					$html = str_replace( 'height="1" ', sprintf( 'height="%s" ', $height ), $html );
+				if ( is_array( $dimensions ) && isset( $dimensions['height'], $dimensions['width'] ) ) {
+					$html = str_replace( 'width="1" ', sprintf( 'width="%s" ', $dimensions['width'] ), $html );
+					$html = str_replace( 'height="1" ', sprintf( 'height="%s" ', $dimensions['height'] ), $html );
 				} else {
 					$html = str_replace( 'width="1" ', '', $html );
 					$html = str_replace( 'height="1" ', '', $html );
@@ -777,6 +766,36 @@ protected function str_ends_with( $haystack, $needle ) {
 			return 0 === substr_compare( $haystack, $needle, -$len, $len );
 		}
 
+		/**
+		 * Return custom width or height of the SVG image.
+		 *
+		 * @param int          $id   Image attachment ID.
+		 * @param string|array $size Size of image. Image size or array of width and height values
+		 *                                    (in that order). Default 'thumbnail'.
+		 *
+		 * @return array|bool Width or height of the SVG image, or false if not found.
+		 */
+		protected function get_svg_dimensions( $id, $size ) {
+			$dimensions = $this->svg_dimensions( $id );
+
+			if ( is_array( $size ) ) {
+				$width  = $size[0];
+				$height = $size[1];
+			} elseif ( 'full' === $size && is_array( $dimensions ) && isset( $dimensions['width'], $dimensions['height'] ) ) {
+				$width  = $dimensions['width'];
+				$height = $dimensions['height'];
+			} else {
+				$width  = get_option( "{$size}_size_w", false );
+				$height = get_option( "{$size}_size_h", false );
+			}
+
+			if ( $dimensions ) {
+				$dimensions['width']  = $width;
+				$dimensions['height'] = $height;
+			}
+
+			return $dimensions;
+		}
 	}
 }
 
diff --git a/tests/unit/test-safe-svg.php b/tests/unit/test-safe-svg.php
index dd4881a..a7b4c56 100644
--- a/tests/unit/test-safe-svg.php
+++ b/tests/unit/test-safe-svg.php
@@ -208,6 +208,7 @@ public function test_one_pixel_fix() {
 				'return_in_order' => array(
 					__DIR__ . '/files/svgCleanOne.svg',
 					__DIR__ . '/files/svgNoDimensions.svg',
+					__DIR__ . '/files/svgCleanOne.svg',
 				),
 			)
 		);
@@ -274,7 +275,7 @@ public function test_one_pixel_fix() {
 		);
 
 		// Test SVG Dimensions
-		$image_sizes = $this->instance->one_pixel_fix( array(), 1, 'thumbnail', false );
+		$image_sizes = $this->instance->one_pixel_fix( array(), 1, 'full', false );
 		if ( ! empty( $image_sizes ) ) {
 			$image_sizes = array_map( 'intval', $image_sizes );
 		}
@@ -298,6 +299,19 @@ public function test_one_pixel_fix() {
 			),
 			$image_sizes
 		);
+
+		// Test Custom Dimensions
+		$image_sizes = $this->instance->one_pixel_fix( array(), 1, [ 500, 500 ], false );
+		if ( ! empty( $image_sizes ) ) {
+			$image_sizes = array_map( 'intval', $image_sizes );
+		}
+		$this->assertSame(
+			array(
+				1 => 500,
+				2 => 500,
+			),
+			$image_sizes
+		);
 	}
 
 	/**