diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 1030b50..d14840a 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -3,16 +3,14 @@ gradle-starter = "0.67.0"
 gradle-doctor = "0.9.1"
 maven-junit = "5.10.1"
 maven-assertj = "3.24.2"
-maven-commons = "2.15.1"
 maven-binarycompatiblity = "0.13.2"
 maven-dokka = "1.9.10"
 
 [libraries]
-kotlin-gradle = { module = "org.jetbrains.kotlin:kotlin-gradle-plugin" }
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "maven-junit" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "maven-junit" }
+junit-jupiter-platform = { module = "org.junit.platform:junit-platform-launcher" }
 assertj-core = { module = "org.assertj:assertj-core", version.ref = "maven-assertj" }
-commons-io = { module = "commons-io:commons-io", version.ref = "maven-commons" }
 jetbrains-dokka = { module = "org.jetbrains.dokka:dokka-gradle-plugin", version.ref = "maven-dokka" }
 
 [plugins]
diff --git a/webp-imageio/build.gradle b/webp-imageio/build.gradle
index 7258f5c..0655b4f 100644
--- a/webp-imageio/build.gradle
+++ b/webp-imageio/build.gradle
@@ -58,5 +58,6 @@ tasks.named("processResources") {
 dependencies {
     testImplementation(libs.assertj.core)
     testRuntimeOnly(libs.junit.jupiter.engine)
+    testRuntimeOnly(libs.junit.jupiter.platform)
     testImplementation(libs.junit.jupiter.api)
 }
diff --git a/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/WebPImageWriterSpi.kt b/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/WebPImageWriterSpi.kt
index c32e0cc..12869b5 100644
--- a/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/WebPImageWriterSpi.kt
+++ b/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/WebPImageWriterSpi.kt
@@ -67,10 +67,6 @@ public open class WebPImageWriterSpi :
                 return false
             }
         }
-        val colorSpace = colorModel.colorSpace
-        if (!colorSpace.isCS_sRGB) {
-            return false
-        }
         val sampleSize = sampleModel.sampleSize
         for (i in sampleSize.indices) {
             if (sampleSize[i] > 8) {
diff --git a/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/internal/WebPWriter.kt b/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/internal/WebPWriter.kt
index 20e5207..4463867 100644
--- a/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/internal/WebPWriter.kt
+++ b/webp-imageio/src/main/kotlin/com/luciad/imageio/webp/internal/WebPWriter.kt
@@ -97,7 +97,8 @@ internal class WebPWriter(originatingProvider: ImageWriterSpi?) : ImageWriter(or
             val width = aRi.width
             val height = aRi.height
             val colorModel = aRi.colorModel
-            return if (colorModel is ComponentColorModel) {
+            val colorSpace = colorModel.colorSpace
+            return if (colorSpace.isCS_sRGB && colorModel is ComponentColorModel) {
                 val sampleModel = aRi.sampleModel as ComponentSampleModel
                 when (sampleModel.transferType) {
                     DataBuffer.TYPE_BYTE -> extractComponentRGBByte(
@@ -116,7 +117,7 @@ internal class WebPWriter(originatingProvider: ImageWriterSpi?) : ImageWriter(or
 
                     else -> throw IOException("Incompatible image: $aRi")
                 }
-            } else if (colorModel is DirectColorModel) {
+            } else if (colorSpace.isCS_sRGB && colorModel is DirectColorModel) {
                 val sampleModel = aRi.sampleModel as SinglePixelPackedSampleModel
                 val type = sampleModel.transferType
                 if (type == DataBuffer.TYPE_INT) {
diff --git a/webp-imageio/src/test/kotlin/com/luciad/imageio/webp/WebPTest.kt b/webp-imageio/src/test/kotlin/com/luciad/imageio/webp/WebPTest.kt
index 3482fc2..996720e 100644
--- a/webp-imageio/src/test/kotlin/com/luciad/imageio/webp/WebPTest.kt
+++ b/webp-imageio/src/test/kotlin/com/luciad/imageio/webp/WebPTest.kt
@@ -8,6 +8,8 @@ import com.luciad.imageio.webp.utils.requireWebpImageWriter
 import com.luciad.imageio.webp.utils.writeWebpImage
 import org.assertj.core.api.Assertions.assertThat
 import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.condition.DisabledOnJre
+import org.junit.jupiter.api.condition.JRE
 import org.junit.jupiter.api.io.TempDir
 import java.awt.image.BufferedImage
 import java.awt.image.DataBufferInt
@@ -83,6 +85,25 @@ class WebPTest {
         assertThat(image.height).isEqualTo(301)
     }
 
+    @Test
+    @DisabledOnJre(JRE.JAVA_9) // for some reason Java 9 can't read JPEGs with indexed colors
+    fun nonRgbColorSpace(@TempDir tempDir: Path) {
+        val inputImage1 = ImageIO.read(readResource("non_rgb_1.jpg").inputStream())
+        val inputImage2 = ImageIO.read(readResource("non_rgb_2.jpeg").inputStream())
+        val outputFile1 = tempDir.resolve("out_1.webp").toFile()
+        val outputFile2 = tempDir.resolve("out_2.webp").toFile()
+
+        ImageIO.write(inputImage1, "webp", outputFile1).let(::check)
+        ImageIO.write(inputImage2, "webp", outputFile2).let(::check)
+        val outputImage1 = readImage(webp = outputFile1.readBytes())
+        val outputImage2 = readImage(webp = outputFile2.readBytes())
+
+        assertThat(outputImage1.width).isEqualTo(500)
+        assertThat(outputImage1.height).isEqualTo(333)
+        assertThat(outputImage2.width).isEqualTo(1000)
+        assertThat(outputImage2.height).isEqualTo(1000)
+    }
+
     @Test
     fun testCompress() {
         val image = BufferedImage(256, 256, BufferedImage.TYPE_INT_ARGB)
diff --git a/webp-imageio/src/test/resources/non_rgb_1.jpg b/webp-imageio/src/test/resources/non_rgb_1.jpg
new file mode 100644
index 0000000..a489c0d
Binary files /dev/null and b/webp-imageio/src/test/resources/non_rgb_1.jpg differ
diff --git a/webp-imageio/src/test/resources/non_rgb_2.jpeg b/webp-imageio/src/test/resources/non_rgb_2.jpeg
new file mode 100644
index 0000000..6ee2d69
Binary files /dev/null and b/webp-imageio/src/test/resources/non_rgb_2.jpeg differ