Crash report "java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.lastIndexOf(int)' on a null object reference"

[K1rakishou]

E/Kuroba | UNCAUGHT: Called from unhandled exception handler.
E/Kuroba | UNCAUGHT: java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.String.lastIndexOf(int)' on a null object reference
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.utils.StringUtils.extractFileNameExtension(StringUtils.java:54)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.core.presenter.ReplyPresenter.showPreview(ReplyPresenter.java:599)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.core.presenter.ReplyPresenter.onFilePicked(ReplyPresenter.java:491)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.ui.helper.ImagePickDelegate$1.onSuccess(ImagePickDelegate.java:173)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.core.cache.FileCacheV2$handleResults$3.invoke(FileCacheV2.kt:643)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.core.cache.FileCacheV2$handleResults$3.invoke(FileCacheV2.kt:46)
E/Kuroba | UNCAUGHT: 	at com.github.adamantcheese.chan.core.cache.FileCacheV2$resultHandler$1$1.run(FileCacheV2.kt:795)
E/Kuroba | UNCAUGHT: 	at android.os.Handler.handleCallback(Handler.java:739)
E/Kuroba | UNCAUGHT: 	at android.os.Handler.dispatchMessage(Handler.java:95)
E/Kuroba | UNCAUGHT: 	at android.os.Looper.loop(Looper.java:158)
E/Kuroba | UNCAUGHT: 	at android.app.ActivityThread.main(ActivityThread.java:7224)
E/Kuroba | UNCAUGHT: 	at java.lang.reflect.Method.invoke(Native Method)
E/Kuroba | UNCAUGHT: 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
E/Kuroba | UNCAUGHT: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
E/Kuroba | UNCAUGHT: ------------------------------
E/Kuroba | UNCAUGHT: END OF CURRENT RUNTIME MESSAGES
E/Kuroba | UNCAUGHT: ------------------------------
E/Kuroba | UNCAUGHT: Android API Level: 23
E/Kuroba | UNCAUGHT: App Version: v4.12.0
E/Kuroba | UNCAUGHT: Development Build: Release
E/Kuroba | UNCAUGHT: Phone Model: samsung SM-G900V