diff --git a/pkg/captcha/inmemdb/inmemdb.go b/pkg/captcha/inmemdb/inmemdb.go
index 1fd697c..90a839c 100644
--- a/pkg/captcha/inmemdb/inmemdb.go
+++ b/pkg/captcha/inmemdb/inmemdb.go
@@ -8,6 +8,7 @@ import (
 	"git.arav.top/Arav/justcaptcha/pkg/captcha"
 )
 
+// InMemoryCaptchaDB implementation that lives in a memory (map).
 type InMemoryCaptchaDB struct {
 	sync.Mutex
 
@@ -17,7 +18,8 @@ type InMemoryCaptchaDB struct {
 }
 
 // NewInMemoryCaptchaDB returns an initialised instance of an InMemoryCaptchaDB.
-// An expiry duration is a time for how long CAPTCHA will be valid.
+// An expiry is a scan interval for expired CAPTCHAs (if passed a longer one,
+// resets to a default (captcha.DefaultExpiredScanInterval)).
 func NewInMemoryCaptchaDB(expiry time.Duration) *InMemoryCaptchaDB {
 	db := &InMemoryCaptchaDB{
 		db:     make(map[captcha.ID]captcha.Captcha),
@@ -34,7 +36,7 @@ func NewInMemoryCaptchaDB(expiry time.Duration) *InMemoryCaptchaDB {
 	return db
 }
 
-// New accepts a CAPTHA instance, generates an ID and store it in a database.
+// New accepts a CAPTCHA instance, generates an ID and store it in a database.
 // A data string is an additional random data used to generate an ID,
 // e.g. an IP-address.
 func (imcdb *InMemoryCaptchaDB) New(data string, cptcha captcha.Captcha) (captcha.Captcha, captcha.ID) {
@@ -47,12 +49,13 @@ func (imcdb *InMemoryCaptchaDB) New(data string, cptcha captcha.Captcha) (captch
 	return cptcha, id
 }
 
-// GetExpiry returns time for how long CAPTCHA will last.
+// GetExpiry returns an expiry for a CAPTCHA.
 func (imcdb *InMemoryCaptchaDB) GetExpiry() time.Duration {
 	return imcdb.expiry
 }
 
-// SetExpiry changes an expiry duration to a new one.
+// SetExpiry changes an expiry for a CAPTCHA and a scan interval. Scan interval
+// cannot be longer than a default, so if it is, then resets to a default.
 func (imcdb *InMemoryCaptchaDB) SetExpiry(expiry time.Duration) {
 	imcdb.expiry = expiry
 	if expiry < captcha.DefaultExpiredScanInterval {
@@ -62,7 +65,8 @@ func (imcdb *InMemoryCaptchaDB) SetExpiry(expiry time.Duration) {
 	}
 }
 
-// Image returns a freshly generated image for a CAPTCHA.
+// Image returns a freshly generated image for a CAPTCHA with style if
+// applicable.
 func (imcdb *InMemoryCaptchaDB) Image(id captcha.ID, style string) *image.Image {
 	imcdb.Lock()
 	defer imcdb.Unlock()