Error shows while adding image in block.

Problem/Motivation

While trying to add image in background it shows the notice as

Undefined index: image in Drupal\advanced_title_block\Plugin\Block\AdvancedTitleBlock->blockSubmit() (line 114 of /app/modules/contrib/advanced_title_block/src/Plugin/Block/AdvancedTitleBlock.php)

Also it changes box size.

Steps to reproduce

• Add block in content region.
• Add background image.
• Set ALT text, background color, add some text.
• Place block and save.
• It will shows the error.

Proposed resolution

Need to change image load path.

Remaining tasks

User interface changes

API changes

Data model changes