Primefaces crop converter error - jsf-2

Question

I am using the following code and try to crop an image which takes its value from a bean :
<p:panelGrid columns="2">
<p:row>
<p:column>
<p:imageCropper id="imageCropperId" value="#{imageCropperBean.croppedImage}"
image="#{imageCropperBean.newImageName}">
</p:imageCropper>
</p:column>
<p:column>Bild innerhalb des Rahmens positionieren</p:column>
<p:column>
<p:graphicImage id="localCroppedImage" value="#{imageCropperBean.newImageName}" />
</p:column>
</p:row>
<p:row>
<p:column colspan="3">
<p:commandButton value="Crop" actionListener="#{imageCropperBean.crop}"
update=":growl imageCropperId localCroppedImage" />
</p:column>
</p:row>
</p:panelGrid>
I am always getting the error : {0}: Conversion error occurred. inside growl, due to :
value="#{imageCropperBean.croppedImage}"
The converter attribute from declaration says :
An el expression or a literal text that defines a converter for the
component. When it's an EL expression, it's resolved to a converter
instance. In case it's a static text, it must refer to a converter id.
but the EL expression is evaluated at String. What should I do? It works if I put a normal String pointing to an existing image.

Answer 1

I have managed to fix this error.
For the ones which will have the same problem, basically this occurs when
Either errors are being thrown during cropping phase (e.g. files not found or if the cropped image is not relative to the original one)
Either the value which is evaluated from EL image="#{imageCropperBean.newImageName}" is evaluated to null, while trying to skip the cropping (I couldn't suceed with required="true" so I used rendering="someCondition")