invalid sharepoint app package. error: part uri is not valid per rules defined in the open packaging

Hello, 
This is my first post on this blog. I am facing an issue with SharePoint. When I upload the Solution-Package file it throws an error that says: "invalid SharePoint app package. error: part URI is not valid per rules defined in the open packaging conventions specification." I have checked all the solutions which are provided in different forum but those are not helping.

the problem I am facing this issue when i try to load the image name from the manifest file. 

In the first Image where ${defaultImage1} is written this is coming from the manifest file. and in the manifest file, the value of this variable is "blogImg1.jpg" "blogImg2.jpg" and so on

When I only made this change and serve the project locally and test it on workbench it was working fine. But When i upload the package file then it throws the the error. Screenshot of error is given in second image.

I have run the following commands to create a package file

1- gulp clean

2- gulp bundle --ship

3- gulp package-solution --ship

can someone help me with this issue why is it occuring.

any suggestions or help will be appriciated

Thanks