Unable to load shared library “libgdiplus” – Docker [ .NET application with Aspose API]

You’re installing libgdiplus in your build container image, but not in your final container image. You need to make sure libgdiplus is installed in your final container image.

You can consider amending your Dockerfile like this:

FROM mcr.microsoft.com/dotnet/core/aspnet:3.0 AS base
RUN apt-get update && apt-get install -y libgdiplus

WORKDIR /app
FROM mcr.microsoft.com/dotnet/core/sdk:3.0 AS build
[...]