diff --git a/config.go b/config.go
index f930e2e1..afc9c5e3 100644
--- a/config.go
+++ b/config.go
@@ -75,7 +75,7 @@ func hexFileConfig(b *[]byte, filepath string) {
 	*b = dst[:n]
 }
 
-func presetEnvConfig(p *presets, name string) {
+func presetEnvConfig(p presets, name string) {
 	if env := os.Getenv(name); len(env) > 0 {
 		presetStrings := strings.Split(env, ",")
 
@@ -85,7 +85,7 @@ func presetEnvConfig(p *presets, name string) {
 	}
 }
 
-func presetFileConfig(p *presets, filepath string) {
+func presetFileConfig(p presets, filepath string) {
 	if len(filepath) == 0 {
 		return
 	}
@@ -99,6 +99,10 @@ func presetFileConfig(p *presets, filepath string) {
 	for scanner.Scan() {
 		parsePreset(p, scanner.Text())
 	}
+
+	if err := scanner.Err(); err != nil {
+		log.Fatalf("Failed to read presets file: %s", err)
+	}
 }
 
 type config struct {
@@ -215,8 +219,8 @@ func init() {
 	strEnvConfig(&conf.BaseURL, "IMGPROXY_BASE_URL")
 
 	conf.Presets = make(presets)
-	presetEnvConfig(&conf.Presets, "IMGPROXY_PRESETS")
-	presetFileConfig(&conf.Presets, *presetsPath)
+	presetEnvConfig(conf.Presets, "IMGPROXY_PRESETS")
+	presetFileConfig(conf.Presets, *presetsPath)
 
 	if len(conf.Key) == 0 {
 		log.Fatalln("Key is not defined")
@@ -295,6 +299,8 @@ func init() {
 		}
 	}
 
+	checkPresets(conf.Presets)
+
 	initVips()
 	initDownloading()
 }
diff --git a/presets.go b/presets.go
index d71665f4..c051c7c9 100644
--- a/presets.go
+++ b/presets.go
@@ -1,10 +1,13 @@
 package main
 
-import "strings"
+import (
+	"log"
+	"strings"
+)
 
 type presets map[string]urlOptions
 
-func parsePreset(p *presets, presetStr string) {
+func parsePreset(p presets, presetStr string) {
 	presetStr = strings.Trim(presetStr, " ")
 
 	if len(presetStr) == 0 || strings.HasPrefix(presetStr, "#") {
@@ -14,27 +17,39 @@ func parsePreset(p *presets, presetStr string) {
 	parts := strings.Split(presetStr, "=")
 
 	if len(parts) != 2 {
-		warning("Invalid preset string, omitted: %s", presetStr)
+		log.Fatalf("Invalid preset string: %s", presetStr)
 		return
 	}
 
 	name := strings.Trim(parts[0], " ")
 	if len(name) == 0 {
-		warning("Empty preset name, omitted: %s", presetStr)
+		log.Fatalf("Empty preset name: %s", presetStr)
 		return
 	}
 
 	value := strings.Trim(parts[1], " ")
 	if len(value) == 0 {
-		warning("Empty preset value, omitted: %s", presetStr)
+		log.Fatalf("Empty preset value: %s", presetStr)
 		return
 	}
 
 	optsStr := strings.Split(value, "/")
 
-	if opts, rest := parseURLOptions(optsStr); len(rest) == 0 {
-		(*p)[name] = opts
-	} else {
-		warning("Invalid preset value, omitted: %s", presetStr)
+	opts, rest := parseURLOptions(optsStr)
+
+	if len(rest) > 0 {
+		log.Fatalf("Invalid preset value: %s", presetStr)
+	}
+
+	p[name] = opts
+}
+
+func checkPresets(p presets) {
+	var po processingOptions
+
+	for name, opts := range p {
+		if err := applyProcessingOptions(&po, opts); err != nil {
+			log.Fatalf("Error in preset `%s`: %s", name, err)
+		}
 	}
 }
diff --git a/processing_options.go b/processing_options.go
index 1bc13385..1b110391 100644
--- a/processing_options.go
+++ b/processing_options.go
@@ -280,10 +280,8 @@ func applySharpenOption(po *processingOptions, args []string) error {
 func applyPresetOption(po *processingOptions, args []string) error {
 	for _, preset := range args {
 		if p, ok := conf.Presets[preset]; ok {
-			for name, pargs := range p {
-				if err := applyProcessingOption(po, name, pargs); err != nil {
-					return err
-				}
+			if err := applyProcessingOptions(po, p); err != nil {
+				return err
 			}
 		} else {
 			return fmt.Errorf("Unknown asset: %s", preset)
@@ -358,6 +356,18 @@ func applyProcessingOption(po *processingOptions, name string, args []string) er
 		if err := applyPresetOption(po, args); err != nil {
 			return err
 		}
+	default:
+		return fmt.Errorf("Unknown processing option: %s", name)
+	}
+
+	return nil
+}
+
+func applyProcessingOptions(po *processingOptions, options urlOptions) error {
+	for name, args := range options {
+		if err := applyProcessingOption(po, name, args); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -422,10 +432,8 @@ func parsePathAdvanced(parts []string, acceptHeader string) (string, processingO
 
 	options, urlParts := parseURLOptions(parts)
 
-	for name, args := range options {
-		if err := applyProcessingOption(&po, name, args); err != nil {
-			return "", po, err
-		}
+	if err := applyProcessingOptions(&po, options); err != nil {
+		return "", po, err
 	}
 
 	url, extension, err := decodeURL(urlParts)