The issue you're experiencing with images not displaying correctly in the Spine Essential version is likely due to the use of meshes in your project. Meshes are a feature exclusive to Spine Professional, and they are not supported in the Essential version. When you open a project that uses meshes in Spine Essential, the images associated with those meshes will not display, and you will see a placeholder image indicating that the Professional version is required. This is a common situation when transitioning from the trial version, which includes all Professional features, to the Essential version.
If you need to work with meshes, you would need to upgrade to the Spine Professional version. Alternatively, you can modify your project to not use meshes if you wish to continue using the Essential version.