An image may be displayed in contexts that trim or cover parts of its edges. You cannot predict every surface, but you can avoid placing the only essential clue at the extreme boundary.
Identify the indispensable content
Mark the subject, key action, and any necessary wording. Keep these comfortably inside the composition. Decorative texture and nonessential background can occupy the outer areas.
Test a few crops
Make temporary narrower and shorter previews without changing the original. Check whether the subject remains recognizable and whether a clipped word changes the meaning. This is a robustness exercise, not a guarantee about a platform's current display rules.
Adjust the source layout
If the message collapses under a modest crop, move the key elements inward or reduce their number. Do not shrink everything until it becomes unreadable. Keep a full-size master and verify the actual destination preview before publishing, since a theoretical safe area cannot replace looking at the real result.