diff --git a/src/main/java/org/codelibs/fess/thumbnail/impl/BaseThumbnailGenerator.java b/src/main/java/org/codelibs/fess/thumbnail/impl/BaseThumbnailGenerator.java
index 66b5f8b86..67ea242fa 100644
--- a/src/main/java/org/codelibs/fess/thumbnail/impl/BaseThumbnailGenerator.java
+++ b/src/main/java/org/codelibs/fess/thumbnail/impl/BaseThumbnailGenerator.java
@@ -15,7 +15,9 @@
  */
 package org.codelibs.fess.thumbnail.impl;
 
+import static org.codelibs.core.stream.StreamUtil.stream;
 import java.io.File;
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -34,7 +36,9 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
 
     protected int directoryNameLength = 5;
 
-    public List<String> generatorList;
+    protected List<String> generatorList;
+
+    protected Map<String, String> filePathMap = new HashMap<>();
 
     public void addCondition(final String key, final String regex) {
         conditionMap.put(key, regex);
@@ -54,7 +58,31 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
     @Override
     public boolean isAvailable() {
         if (generatorList != null && !generatorList.isEmpty()) {
-            return generatorList.stream().allMatch(s -> new File(s).isFile());
+            String path = System.getenv("PATH");
+            if (path == null) {
+                path = System.getenv("Path");
+            }
+            if (path == null) {
+                path = System.getenv("path");
+            }
+            final List<String> pathList = new ArrayList<>();
+            pathList.add("/usr/share/fess/bin");
+            if (path != null) {
+                stream(path.split(File.pathSeparator)).of(stream -> stream.map(s -> s.trim()).forEach(s -> pathList.add(s)));
+            }
+            return generatorList.stream().map(s -> {
+                if (s.startsWith("${path}")) {
+                    for (String p : pathList) {
+                        final File f = new File(s.replace("${path}", p));
+                        if (f.exists()) {
+                            final String filePath = f.getAbsolutePath();
+                            filePathMap.put(s, filePath);
+                            return filePath;
+                        }
+                    }
+                }
+                return s;
+            }).allMatch(s -> new File(s).isFile());
         }
         return true;
     }
@@ -63,4 +91,15 @@ public abstract class BaseThumbnailGenerator implements ThumbnailGenerator {
         this.directoryNameLength = directoryNameLength;
     }
 
+    protected String expandPath(String value) {
+        if (value != null && filePathMap.containsKey(value)) {
+            return filePathMap.get(value);
+        }
+        return value;
+    }
+
+    public void setGeneratorList(List<String> generatorList) {
+        this.generatorList = generatorList;
+    }
+
 }
\ No newline at end of file
diff --git a/src/main/java/org/codelibs/fess/thumbnail/impl/CommandGenerator.java b/src/main/java/org/codelibs/fess/thumbnail/impl/CommandGenerator.java
index e2a0fa4a7..aa5cd3db9 100644
--- a/src/main/java/org/codelibs/fess/thumbnail/impl/CommandGenerator.java
+++ b/src/main/java/org/codelibs/fess/thumbnail/impl/CommandGenerator.java
@@ -81,7 +81,7 @@ public class CommandGenerator extends BaseThumbnailGenerator {
         final String outputPath = outputFile.getAbsolutePath();
         final List<String> cmdList = new ArrayList<>();
         for (final String value : commandList) {
-            cmdList.add(value.replace("${url}", url).replace("${outputFile}", outputPath));
+            cmdList.add(expandPath(value.replace("${url}", url).replace("${outputFile}", outputPath)));
         }
 
         ProcessBuilder pb = null;
diff --git a/src/main/java/org/codelibs/fess/thumbnail/impl/WebDriverGenerator.java b/src/main/java/org/codelibs/fess/thumbnail/impl/WebDriverGenerator.java
index 9d06651de..cd90904ac 100644
--- a/src/main/java/org/codelibs/fess/thumbnail/impl/WebDriverGenerator.java
+++ b/src/main/java/org/codelibs/fess/thumbnail/impl/WebDriverGenerator.java
@@ -31,6 +31,7 @@ import org.openqa.selenium.OutputType;
 import org.openqa.selenium.TakesScreenshot;
 import org.openqa.selenium.WebDriver;
 import org.openqa.selenium.phantomjs.PhantomJSDriver;
+import org.openqa.selenium.remote.DesiredCapabilities;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -52,16 +53,28 @@ public class WebDriverGenerator extends BaseThumbnailGenerator {
 
     @PostConstruct
     public void init() {
-        try {
-            if (webDriver == null) {
-                webDriver = webDriverCapabilities == null ? new PhantomJSDriver() : new PhantomJSDriver(webDriverCapabilities);
-            }
-            webDriver.manage().window().setSize(new Dimension(windowWidth, windowHeight));
-        } catch (final Exception e) {
-            if (logger.isDebugEnabled()) {
-                logger.debug("WebDriver is not available for generating thumbnails.", e);
-            } else {
-                logger.info("WebDriver is not available for generating thumbnails.");
+        if (super.isAvailable()) {
+            try {
+                if (webDriver == null) {
+                    if (webDriverCapabilities == null) {
+                        webDriver = new PhantomJSDriver();
+                    } else {
+                        if (webDriverCapabilities instanceof DesiredCapabilities) {
+                            DesiredCapabilities capabilities = (DesiredCapabilities) webDriverCapabilities;
+                            webDriverCapabilities.asMap().entrySet().stream()
+                                    .filter(e -> e.getValue() instanceof String && filePathMap.containsKey(e.getValue().toString()))
+                                    .forEach(e -> capabilities.setCapability(e.getKey(), filePathMap.get(e.getValue().toString())));
+                        }
+                        webDriver = new PhantomJSDriver(webDriverCapabilities);
+                    }
+                }
+                webDriver.manage().window().setSize(new Dimension(windowWidth, windowHeight));
+            } catch (final Exception e) {
+                if (logger.isDebugEnabled()) {
+                    logger.debug("WebDriver is not available for generating thumbnails.", e);
+                } else {
+                    logger.info("WebDriver is not available for generating thumbnails.");
+                }
             }
         }
     }
diff --git a/src/main/resources/fess_thumbnail.xml b/src/main/resources/fess_thumbnail.xml
index 930554d82..b331b824c 100644
--- a/src/main/resources/fess_thumbnail.xml
+++ b/src/main/resources/fess_thumbnail.xml
@@ -11,11 +11,14 @@
 		</postConstruct>
 	</component>
 	<component name="htmlThumbnailGenerator" class="org.codelibs.fess.thumbnail.impl.WebDriverGenerator">
+		<property name="generatorList">
+			["${path}/phantomjs"]
+		</property>
 		<property name="webDriverCapabilities">
 			<component class="org.openqa.selenium.remote.DesiredCapabilities">
 				<postConstruct name="setCapability">
 					<arg>"phantomjs.binary.path"</arg>
-					<arg>"/usr/bin/phantomjs"</arg>
+					<arg>"${path}/phantomjs"</arg>
 				</postConstruct>
 			</component>
 		</property>
@@ -27,13 +30,13 @@
 <!--
 	<component name="htmlThumbnailGenerator" class="org.codelibs.fess.thumbnail.impl.CommandGenerator">
 		<property name="commandList">
-			["/usr/share/fess/bin/generate-thumbnail",
+			["${path}/generate-thumbnail",
 			"html",
 			"${url}",
 			"${outputFile}"]
 		</property>
 		<property name="generatorList">
-			["/usr/share/fess/bin/generate-thumbnail"]
+			["${path}/generate-thumbnail"]
 		</property>
 		<postConstruct name="addCondition">
 			<arg>"mimetype"</arg>
@@ -43,13 +46,13 @@
 -->
 	<component name="msofficeThumbnailGenerator" class="org.codelibs.fess.thumbnail.impl.CommandGenerator">
 		<property name="commandList">
-			["/usr/share/fess/bin/generate-thumbnail",
+			["${path}/generate-thumbnail",
 			"msoffice",
 			"${url}",
 			"${outputFile}"]
 		</property>
 		<property name="generatorList">
-			["/usr/share/fess/bin/generate-thumbnail"]
+			["${path}/generate-thumbnail"]
 		</property>
 		<postConstruct name="addCondition">
 			<arg>"mimetype"</arg>