diff --git a/Eve-O-Preview/Configuration/AppConfig.cs b/Eve-O-Preview/Configuration/AppConfig.cs
index 150bb52..f78f891 100644
--- a/Eve-O-Preview/Configuration/AppConfig.cs
+++ b/Eve-O-Preview/Configuration/AppConfig.cs
@@ -157,5 +157,32 @@ namespace EveOPreview.Configuration
 		{
 			this.ClientHotkey[currentClient] = (new KeysConverter()).ConvertToInvariantString(hotkey);
 		}
+
+		/// <summary>
+		/// Applies restrictions to different parameters of the config
+		/// </summary>
+		public void ApplyRestrictions()
+		{
+			this.ThumbnailRefreshPeriod = AppConfig.ApplyRestrictions(this.ThumbnailRefreshPeriod, 300, 1000);
+			this.ThumbnailSize = new Size(AppConfig.ApplyRestrictions(this.ThumbnailSize.Width, this.ThumbnailMinimumSize.Width, this.ThumbnailMaximumSize.Width),
+				AppConfig.ApplyRestrictions(this.ThumbnailSize.Height, this.ThumbnailMinimumSize.Height, this.ThumbnailMaximumSize.Height));
+			this.ThumbnailOpacity = AppConfig.ApplyRestrictions((int)(this.ThumbnailOpacity * 100.00), 20, 100) / 100.00;
+			this.ThumbnailZoomFactor = AppConfig.ApplyRestrictions(this.ThumbnailZoomFactor, 2, 10);
+		}
+
+		private static int ApplyRestrictions(int value, int minimum, int maximum)
+		{
+			if (value <= minimum)
+			{
+				return minimum;
+			}
+
+			if (value >= maximum)
+			{
+				return maximum;
+			}
+
+			return value;
+		}
 	}
 }
\ No newline at end of file
diff --git a/Eve-O-Preview/Configuration/ConfigurationStorage.cs b/Eve-O-Preview/Configuration/ConfigurationStorage.cs
index 076d967..513b73e 100644
--- a/Eve-O-Preview/Configuration/ConfigurationStorage.cs
+++ b/Eve-O-Preview/Configuration/ConfigurationStorage.cs
@@ -24,6 +24,9 @@ namespace EveOPreview.Configuration
 			string rawData = File.ReadAllText(ConfigurationStorage.ConfigurationFileName);
 
 			JsonConvert.PopulateObject(rawData, this._configuration);
+
+			// Validate data after loading it
+			this._configuration.ApplyRestrictions();
 		}
 
 		public void Save()
diff --git a/Eve-O-Preview/Configuration/IAppConfig.cs b/Eve-O-Preview/Configuration/IAppConfig.cs
index 3c75043..5e2cd81 100644
--- a/Eve-O-Preview/Configuration/IAppConfig.cs
+++ b/Eve-O-Preview/Configuration/IAppConfig.cs
@@ -38,5 +38,7 @@ namespace EveOPreview.Configuration
 
 		Keys GetClientHotkey(string currentClient);
 		void SetClientHotkey(string currentClient, Keys hotkey);
+
+		void ApplyRestrictions();
 	}
 }
\ No newline at end of file