Change Sharepoint Icon in a new ribbon - sharepoint

Question

'm trying to add a ribbon in my project server site and it's working but I'm currently looking for a way to change my icon
Here the code I use:
<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
<CustomAction Id="d6e0a4c1-19a9-4846-92fb-d0593aa3bbfc.myAppNewFormAction"
RegistrationType="List"
RegistrationId="115"
Location="CommandUI.Ribbon"
Sequence="10001"
Title="New myApp Form">
<CommandUIExtension>
<!--
Update the UI definitions below with the controls and the command actions
that you want to enable for the custom action.
-->
<CommandUIDefinitions>
<CommandUIDefinition Location="Ribbon.Documents.New.Controls._children">
<Button Id="Ribbon.Documents.New.myAppNewFormActionButton"
Alt="New myApp Form"
Sequence="100"
Command="Invoke_myAppNewFormActionButtonRequest"
LabelText="New myApp Form"
TemplateAlias="o1"
Image32by32="Mysite/Pwa/ImageFolders/myAppLogoBug-onwhite-32.png"
Image16by16="Mysite/Pwa/ImageFolders/myAppLogoBug-onwhite-16.png" />
</CommandUIDefinition>
</CommandUIDefinitions>
<CommandUIHandlers>
<CommandUIHandler Command="Invoke_myAppNewFormActionButtonRequest"
CommandAction="~appWebUrl/Pages/Default.aspx?Action=New&Source={Source}&ListURLDir={ListUrlDir}"/>
</CommandUIHandlers>
</CommandUIExtension >
</CustomAction>
</Elements>
So on my project server; I created a list in which I stored my image but it's not working, the icon shows me an empty case
I also tried to convert my image in base 64 but the result is the same :/
Any idea of what I'm doing wrong?

Answer 1

My test demo for your reference.
<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
<CustomAction Id="cfe1a724-53ea-4a66-acda-7bc69c2fff1c.CustomRibbonImage"
RegistrationType="List"
RegistrationId="{$ListId:OOBDoc;}"
Location="CommandUI.Ribbon"
Sequence="10001"
Title="Invoke &apos;CustomRibbonImage&apos; action">
<CommandUIExtension>
<!--
Update the UI definitions below with the controls and the command actions
that you want to enable for the custom action.
-->
<CommandUIDefinitions>
<CommandUIDefinition Location="Ribbon.Documents.New.Controls._children">
<Button Id="Ribbon.Documents.New.CustomRibbonImageButton"
Alt="Request CustomRibbonImage"
Sequence="100"
Command="Invoke_CustomRibbonImageButtonRequest"
LabelText="Request CustomRibbonImage"
TemplateAlias="o1"
Image32by32="~sitecollection/SiteAssets/test.png"
Image16by16="~sitecollection/SiteAssets/test.png" />
</CommandUIDefinition>
</CommandUIDefinitions>
<CommandUIHandlers>
<CommandUIHandler Command="Invoke_CustomRibbonImageButtonRequest"
CommandAction="~appWebUrl/Pages/Default.aspx?{StandardTokens}&SPListItemId={SelectedItemId}&SPListId={SelectedListId}"/>
</CommandUIHandlers>
</CommandUIExtension >
</CustomAction>
</Elements>